Control Channel in a Wireless Communication System

ABSTRACT

A base station receives channel state information from a wireless device. The base station transmits to the wireless device one or more data packets on a data channel employing a first precoding matrix identifier. The base station transmits one or more control packets on a control channel to the wireless device employing a second precoding matrix.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Non-Provisional applicationSer. No. 13/887,408, filed May 6, 2013, now U.S. Pat. No. 9,949,265,which claims the benefit of U.S. Provisional Application No. 61/642,472,filed May 4, 2012. The contents of these applications are herebyincorporated by reference in their entirety.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Examples of several of the various embodiments of the present inventionare described herein with reference to the drawings, in which:

FIG. 1 is a diagram depicting example sets of OFDM subcarriers accordingto an exemplary embodiment;

FIG. 2 is a diagram depicting an example transmission and reception timefor two carriers, according to an exemplary embodiment;

FIG. 3 is a diagram depicting OFDM radio resources according to anexemplary embodiment;

FIG. 4 is a block diagram of a base station and a wireless device,according to an exemplary embodiment;

FIG. 5 is a diagram depicting time and frequency resources for twocarriers according to an exemplary embodiment; and

FIG. 6 is a diagram illustrating transmission of data and controlinformation according to an exemplary embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Example embodiments of the present invention disclose a control channelin a wireless communication system. Embodiments of the technologydisclosed herein may be employed in the technical field of wirelesscommunication systems. More particularly, the embodiments of thetechnology disclosed herein may relate to transmission of reception of acontrol channel in a wireless communication system.

Example embodiments of the invention may be implemented using variousphysical layer modulation and transmission mechanisms. Exampletransmission mechanisms may include, but are not limited to: CDMA (codedivision multiple access), OFDM (orthogonal frequency divisionmultiplexing), TDMA (time division multiple access), Wavelettechnologies, and/or the like. Hybrid transmission mechanisms such asTDMA/CDMA, and OFDM/CDMA may also be employed. Various modulationschemes may be applied for signal transmission in the physical layer.Examples of modulation schemes include, but are not limited to: phase,amplitude, code, a combination of these, and/or the like. An exampleradio transmission method may implement QAM (quadrature amplitudemodulation) using BPSK (binary phase shift keying), QPSK (quadraturephase shift keying), 16-QAM, 64-QAM, 256-QAM, and/or the like. Physicalradio transmission may be enhanced by dynamically or semi-dynamicallychanging the modulation and coding scheme depending on transmissionrequirements and radio conditions.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present invention. As illustrated in thisexample, arrow(s) in the diagram may depict a subcarrier in amulticarrier OFDM system. The OFDM system may use technology such asOFDM technology, SC-OFDM (single carrier-OFDM) technology, or the like.For example, arrow 101 shows a subcarrier transmitting informationsymbols. FIG. 1 is for illustration purposes, and a typical multicarrierOFDM system may include more subcarriers in a carrier. For example, thenumber of subcarriers in a carrier may be in the range of 10 to 10,000subcarriers. FIG. 1 shows two guard bands 106 and 107 in a transmissionband. As illustrated in FIG. 1, guard band 106 is between subcarriers103 and subcarriers 104. The example set of subcarriers A 102 includessubcarriers 103 and subcarriers 104. FIG. 1 also illustrates an exampleset of subcarriers B 105. As illustrated, there is no guard band betweenany two subcarriers in the example set of subcarriers B 105. Carriers ina multicarrier OFDM communication system may be contiguous carriers,non-contiguous carriers, or a combination of both contiguous andnon-contiguous carriers.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers as per an aspect of an embodiment of the presentinvention. A multicarrier OFDM communication system may include one ormore carriers, for example, ranging from 1 to 10 carriers. Carrier A 204and carrier B 205 may have the same or different timing structures.Although FIG. 2 shows two synchronized carriers, carrier A 204 andcarrier B 205 may or may not be synchronized with each other. Differentradio frame structures may be supported for FDD (frequency divisionduplex) and TDD (time division duplex) duplex mechanisms. FIG. 2 showsan example FDD frame timing. Downlink and uplink transmissions may beorganized into radio frames 201. In this example, radio frame durationis 10 msec. Other frame durations, for example, in the range of 1 to 100msec may also be supported. In this example, each 10 ms radio frame 201may be divided into ten equally sized sub-frames 202. Other subframedurations such as including 0.5 msec, 1 msec, 2 msec, and 5 msec mayalso be supported. Sub-frame(s) may consist of two or more slots 206.For the example of FDD, 10 subframes may be available for downlinktransmission and 10 subframes may be available for uplink transmissionsin each 10 ms interval. Uplink and downlink transmissions may beseparated in the frequency domain. Slot(s) may include a plurality ofOFDM symbols 203. The number of OFDM symbols 203 in a slot 206 maydepend on the cyclic prefix length and subcarrier spacing.

In an example case of TDD, uplink and downlink transmissions may beseparated in the time domain. According to some of the various aspectsof embodiments, each 10 ms radio frame may include two half-frames of 5ms each. Half-frame(s) may include eight slots of length 0.5 ms andthree special fields: DwPTS (Downlink Pilot Time Slot), GP (GuardPeriod) and UpPTS (Uplink Pilot Time Slot). The length of DwPTS andUpPTS may be configurable subject to the total length of DwPTS, GP andUpPTS being equal to 1 ms. Both 5 ms and 10 ms switch-point periodicitymay be supported. In an example, subframe 1 in all configurations andsubframe 6 in configurations with 5 ms switch-point periodicity mayinclude DwPTS, GP and UpPTS. Subframe 6 in configurations with 10 msswitch-point periodicity may include DwPTS. Other subframes may includetwo equally sized slots. For this TDD example, GP may be employed fordownlink to uplink transition. Other subframes/fields may be assignedfor either downlink or uplink transmission. Other frame structures inaddition to the above two frame structures may also be supported, forexample in one example embodiment the frame duration may be selecteddynamically based on the packet sizes.

FIG. 3 is a diagram depicting OFDM radio resources as per an aspect ofan embodiment of the present invention. The resource grid structure intime 304 and frequency 305 is illustrated in FIG. 3. The quantity ofdownlink subcarriers or resource blocks (RB) (in this example 6 to 100RBs) may depend, at least in part, on the downlink transmissionbandwidth 306 configured in the cell. The smallest radio resource unitmay be called a resource element (e.g. 301). Resource elements may begrouped into resource blocks (e.g. 302). Resource blocks may be groupedinto larger radio resources called Resource Block Groups (RBG) (e.g.303). The transmitted signal in slot 206 may be described by one orseveral resource grids of a plurality of subcarriers and a plurality ofOFDM symbols. Resource blocks may be used to describe the mapping ofcertain physical channels to resource elements. Other pre-definedgroupings of physical resource elements may be implemented in the systemdepending on the radio technology. For example, 24 subcarriers may begrouped as a radio block for a duration of 5 msec.

Physical and virtual resource blocks may be defined. A physical resourceblock may be defined as N consecutive OFDM symbols in the time domainand M consecutive subcarriers in the frequency domain, wherein M and Nare integers. A physical resource block may include M.times.N resourceelements. In an illustrative example, a resource block may correspond toone slot in the time domain and 180 kHz in the frequency domain (for 15KHz subcarrier bandwidth and 12 subcarriers). A virtual resource blockmay be of the same size as a physical resource block. Various types ofvirtual resource blocks may be defined (e.g. virtual resource blocks oflocalized type and virtual resource blocks of distributed type). Forvarious types of virtual resource blocks, a pair of virtual resourceblocks over two slots in a subframe may be assigned together by a singlevirtual resource block number. Virtual resource blocks of localized typemay be mapped directly to physical resource blocks such that sequentialvirtual resource block k corresponds to physical resource block k.Alternatively, virtual resource blocks of distributed type may be mappedto physical resource blocks according to a predefined table or apredefined formula. Various configurations for radio resources may besupported under an OFDM framework, for example, a resource block may bedefined as including the subcarriers in the entire band for an allocatedtime duration.

According to some of the various aspects of embodiments, an antenna portmay be defined such that the channel over which a symbol on the antennaport is conveyed may be inferred from the channel over which anothersymbol on the same antenna port is conveyed. In some embodiments, theremay be one resource grid per antenna port. The set of antenna port(s)supported may depend on the reference signal configuration in the cell.Cell-specific reference signals may support a configuration of one, two,or four antenna port(s) and may be transmitted on antenna port(s) {0},{0, 1}, and {0, 1, 2, 3}, respectively. Multicast-broadcast referencesignals may be transmitted on antenna port 4. Wireless device-specificreference signals may be transmitted on antenna port(s) 5, 7, 8, or oneor several of ports {7, 8, 9, 10, 11, 12, 13, 14}. Positioning referencesignals may be transmitted on antenna port 6. Channel state information(CSI) reference signals may support a configuration of one, two, four oreight antenna port(s) and may be transmitted on antenna port(s) 15, {15,16}, {15, . . . , 18} and {15, . . . , 22}, respectively. Variousconfigurations for antenna configuration may be supported depending onthe number of antennas and the capability of the wireless devices andwireless base stations.

According to some embodiments, a radio resource framework using OFDMtechnology may be employed. Alternative embodiments may be implementedemploying other radio technologies. Example transmission mechanismsinclude, but are not limited to: CDMA, OFDM, TDMA, Wavelet technologies,and/or the like. Hybrid transmission mechanisms such as TDMA/CDMA, andOFDM/CDMA may also be employed.

FIG. 4 is an example block diagram of a base station 401 and a wirelessdevice 406, as per an aspect of an embodiment of the present invention.A communication network 400 may include at least one base station 401and at least one wireless device 406. The base station 401 may includeat least one communication interface 402, at least one processor 403,and at least one set of program code instructions 405 stored innon-transitory memory 404 and executable by the at least one processor403. The wireless device 406 may include at least one communicationinterface 407, at least one processor 408, and at least one set ofprogram code instructions 410 stored in non-transitory memory 409 andexecutable by the at least one processor 408. Communication interface402 in base station 401 may be configured to engage in communicationwith communication interface 407 in wireless device 406 via acommunication path that includes at least one wireless link 411.Wireless link 411 may be a bi-directional link. Communication interface407 in wireless device 406 may also be configured to engage in acommunication with communication interface 402 in base station 401. Basestation 401 and wireless device 406 may be configured to send andreceive data over wireless link 411 using multiple frequency carriers.According to some of the various aspects of embodiments, transceiver(s)may be employed. A transceiver is a device that includes both atransmitter and receiver. Transceivers may be employed in devices suchas wireless devices, base stations, relay nodes, and/or the like.Example embodiments for radio technology implemented in communicationinterface 402, 407 and wireless link 411 are illustrated are FIG. 1,FIG. 2, and FIG. 3. and associated text.

An interface may be a hardware interface, a firmware interface, asoftware interface, and/or a combination thereof. The hardware interfacemay include connectors, wires, electronic devices such as drivers,amplifiers, and/or the like. A software interface may include codestored in a memory device to implement protocol(s), protocol layers,communication drivers, device drivers, combinations thereof, and/or thelike. A firmware interface may include a combination of embeddedhardware and code stored in and/or in communication with a memory deviceto implement connections, electronic device operations, protocol(s),protocol layers, communication drivers, device drivers, hardwareoperations, combinations thereof, and/or the like.

The term configured may relate to the capacity of a device whether thedevice is in an operational or non-operational state. Configured mayalso refer to specific settings in a device that effect the operationalcharacteristics of the device whether the device is in an operational ornon-operational state. In other words, the hardware, software, firmware,registers, memory values, and/or the like may be “configured” within adevice, whether the device is in an operational or nonoperational state,to provide the device with specific characteristics. Terms such as “acontrol message to cause in a device” may mean that a control messagehas parameters that may be used to configure specific characteristics inthe device, whether the device is in an operational or non-operationalstate.

According to some of the various aspects of embodiments, an LTE networkmay include many base stations, providing a user plane (PDCP: packetdata convergence protocol/RLC: radio link control/MAC: media accesscontrol/PHY: physical) and control plane (RRC: radio resource control)protocol terminations towards the wireless device. The base station(s)may be interconnected with other base station(s) by means of an X2interface. The base stations may also be connected by means of an S1interface to an EPC (Evolved Packet Core). For example, the basestations may be interconnected to the MME (Mobility Management Entity)by means of the S1-MME interface and to the Serving Gateway (S-GW) bymeans of the S1-U interface. The S1 interface may support a many-to-manyrelation between MMEs/Serving Gateways and base stations. A base stationmay include many sectors for example: 1, 2, 3, 4, or 6 sectors. A basestation may include many cells, for example, ranging from 1 to 50 cellsor more. A cell may be categorized, for example, as a primary cell orsecondary cell. When carrier aggregation is configured, a wirelessdevice may have one RRC connection with the network. At RRC connectionestablishment/re-establishment/handover, one serving cell may providethe NAS (non-access stratum) mobility information (e.g. TAI-trackingarea identifier), and at RRC connection re-establishment/handover, oneserving cell may provide the security input. This cell may be referredto as the Primary Cell (PCell). In the downlink, the carriercorresponding to the PCell may be the Downlink Primary Component Carrier(DL PCC), while in the uplink, it may be the Uplink Primary ComponentCarrier (UL PCC). Depending on wireless device capabilities, SecondaryCells (SCells) may be configured to form together with the PCell a setof serving cells. In the downlink, the carrier corresponding to an SCellmay be a Downlink Secondary Component Carrier (DL SCC), while in theuplink, it may be an Uplink Secondary Component Carrier (UL SCC). AnSCell may or may not have an uplink carrier.

A cell, comprising a downlink carrier and optionally an uplink carrier,is assigned a physical cell ID and a cell index. A carrier (downlink oruplink) belongs to only one cell, the cell ID or Cell index may alsoidentify the downlink carrier or uplink carrier of the cell (dependingon the context it is used). In the specification, cell ID may be equallyreferred to a carrier ID, and cell index may be referred to carrierindex. In implementation, the physical cell ID or cell index may beassigned to a cell. Cell ID may be determined using the synchronizationsignal transmitted on a downlink carrier. Cell index may be determinedusing RRC messages. For example, when the specification refers to afirst physical cell ID for a first downlink carrier, it may mean thefirst physical cell ID is for a cell comprising the first downlinkcarrier. The same concept may apply to, for example, carrier activation.When the specification indicates that a first carrier is activated, itequally means that the cell comprising the first carrier is activated.

Embodiments may be configured to operate as needed. The disclosedmechanism may be performed when certain criteria are met, for example,in wireless device, base station, radio environment, network, acombination of the above, and/or the like. Example criteria may bebased, at least in part, on for example, traffic load, initial systemset up, packet sizes, traffic characteristics, a combination of theabove, and/or the like. When the one or more criteria are met, theexample embodiments may be applied. Therefore, it may be possible toimplement example embodiments that selectively implement disclosedprotocols.

Example embodiments of the invention may disclose a control channel.Other example embodiments may comprise a non-transitory tangiblecomputer readable media comprising instructions executable by one ormore processors to cause transmission and reception of a controlchannel. Yet other example embodiments may comprise an article ofmanufacture that comprises a non-transitory tangible computer readablemachine-accessible medium having instructions encoded thereon forenabling programmable hardware to cause a device (e.g. wirelesscommunicator, UE, base station, etc.) to transmission and reception of acontrol channel. The device may include processors, memory, interfaces,and/or the like. Other example embodiments may comprise communicationnetworks comprising devices such as base stations, wireless devices (oruser equipment: UE), servers, switches, antennas, and/or the like.

According to some of the various aspects of embodiments, a base stationmay receive a first radio resource control (RRC) message from a wirelessdevice (UE). The first message may be received on a primary carrier(uplink) during the connection set up process. The first message may bea UE capability information message. The UE may transfer its radioaccess capability information to the eNB (E-UTRAN). If the UE haschanged its E-UTRAN radio access capabilities, the UE may request higherlayers to initiate a procedure that would result in the update of UEradio access capabilities using a new RRC connection. A UE may be ableto communicate with the E-UTRAN about its radio access capabilities,such as the system (including the release and frequency band) that theUE supports, the UE receive and transmit capabilities (single/dualradio, dual receiver), and/or the like. The first RRC message maycomprise one or more parameters indicating whether the wireless devicesupports an enhanced physical downlink control channel (ePDCCH). Thefirst RRC message may comprise one or more parameters providinginformation (explicitly or implicitly) on whether the wireless devicesupports new carrier types (NCT). Example of NCTs are stand alone NCT,synchronized NCT, unsynchronized NCT, and/or the like.

The base station may transmit selectively and if the one or moreparameters indicates support of ePDCCH, at least one second RRC messageconfigured to cause, in the wireless device, configuration of one ormore ePDCCHs. The base station may receive UE capability informationfrom the wireless device. If the wireless device does not supportePDCCH, then the base station does not configure ePDCCH for the wirelessdevice. If the wireless device indicates that it supports ePDCCHconfiguration, the base station may decide to configure ePDCCH or not toconfigure ePDCCH for the wireless device. This decision is based oninternal base station mechanisms, and may be based, at least in part, onbase station configuration settings, UE QoS profile, UE bearers,mobility, a combination thereof, and/or the like.

The at least one second RRC message configured to cause, in the wirelessdevice, configuration of ePDCCH on existing configured carriers (forexample a primary cell, a secondary cell), or on newly added cells(legacy or NCT cell). The at least one second RRC message may furthercause, in the wireless device, configuration of other radio channels andparameters, such as, uplink data channel, downlink data channel, uplinkcontrol channel, downlink control channel, power control parameters,measurement parameters, radio bearers, a combination thereof, and/or thelike. The at least one second RRC message configuring ePDCCH maycomprise at least one of: subframe subset configuration, ePDCCH startingposition in the subset of subframes, and at least one ePDCCHtransmission and resource configuration. Some of the parameters may beconsidered optional.

According to some of the various aspects of embodiments, an ePDCCH of adownlink carrier may be configured for a subset of subframes in aplurality of subframes. The at least one second RRC message may comprisesubframe configuration information. For example at least one second RRCmessage may comprise a bitmap indicating which subframe(s) in radioframes are configured with ePDCCH resources. The ePDCCH bitmap mayconfigure the subframes which the UE may monitor search space(s) onePDCCH. A UE may monitor a UE-specific search space in ePDCCH radioresources. The bitmap may be for example 40 bits, and may indicate theePDCCH subframes for the duration of four frames. For example, a valueof zero may indicate no ePDCCH resources in the corresponding subframefor the UE, and a value of one may indicate ePDCCH resources areconfigured for the UE in the corresponding subframe. In this example,the same pattern may be repeated in every four frame (40 subframes). Inanother example for TDD frame structure, the bitmap may be 20, 60, or 70bits. If the bitmap is not included in the at least one second messageconfiguring EPDCCH, then ePDCCH may be configured in every subframe. AUE may monitor the UE-specific search space on ePDCCH in all subframesexcept when according to some pre-defined rules when other parameters,for example, measurement parameters, may not allow monitoring of ePDCCHin that subframe.

According to some of the various aspects of embodiments, the at leastone second RRC message may comprise a starting symbol parameterindicating ePDCCH starting symbol in ePDCCH configured subframes. Thestarting symbol parameter may indicate the OFDM starting symbol for anyePDCCH and PDSCH scheduled by ePDCCH on the same cell, if the UE is notconfigured with coordinated multimode transmission mode. If startingsymbol parameter is not present in the RRC message configuring ePDCCH,the UE may derive the starting OFDM symbol of ePDCCH and PDSCH scheduledby the ePDCCH from PCFICH (format indicator parameter) transmitted inthe same subframe. In an example embodiment, values zero, one, two, andthree may applicable for dl-Bandwidth greater than ten resource blocks,and values two, three, and four may be applicable. The starting symbolparameter may not be configured employing the starting symbol parameterwhen UE is configured with coordinated multimode transmission mode.

According to some of the various aspects of embodiments, in a givensubframe of a cell, some of the UEs may be configured with ePDCCH andsome other UEs may not be configured with ePDCCH in the given subframe.The PDSCH starting position in the given subframe for UEs that areconfigured with ePDCCH in the cell may be determined employing thestarting symbol parameter. PDSCH starting position in the given subframefor UEs that are not configured with ePDCCH in the cell may bedetermined employing PCFICH or other RRC messages.

According to some of the various aspects of embodiments, the at leastone second RRC message configuring ePDCCH may comprise at least oneePDCCH transmission and resource configuration. For example, ePDCCH maycomprise one or two ePDCCH transmission and resource configuration. AnePDCCH transmission and resource configuration may be identified by anePDCCH index. The ePDCCH index may be used to add or release ePDCCHtransmission and resource configuration to or from an existingconfigured ePDCCH. The ePDCCH transmission and resource configurationmay comprise one or more parameters, including one or more of thefollowing parameters: frequency resources, frequency distribution,frequency assignment, reference sequence, corresponding uplink controlchannel parameter, and coordinated transmission mode parameters. TheePDCCH transmission and resource configuration may be applicable to thesubset of subframes in which ePDCCH is configured.

According to some of the various aspects of embodiments, frequencyresources parameter may indicate the number of physical resource-blockpairs used for the ePDCCH. For example this may have the value of two,four or six. The frequency distribution parameter may indicate whetherthe frequency resources (resource blocks) are distributed or localized.In localized distribution, resource blocks in ePDCCH transmission may becontiguous, and in a distributed distribution resource blocks in ePDCCHmay be distributed in the carrier bandwidth. The frequency assignmentparameter indicates the assignment of specific resource blocks inresource blocks of LTE carrier to the ePDCCH. The frequency assignment,for example, may be an index to a specific combination of physicalresource-block pairs for ePDCCH set as defined in a pre-defined look-uptable. The reference sequence parameter may indicate the demodulationreference signal scrambling sequence initialization parameter for ePDCCHsymbols. The corresponding uplink control channel parameter may indicatePUCCH format 1a and 1b resource starting offset for the ePDCCH set. Forexample, uplink PUCCH radio resources for transmitting ACK/NACK fordownlink transport blocks (MAC/PHY packets) transmitted in the PDSCHscheduled by ePDCCH is determined based, at least in part, employing thecorresponding uplink control channel parameter. The uplink controlchannel parameter may indicate the frequency start offset in terms ofresource blocks in the uplink carrier. The coordinated transmission modeparameters may indicate the starting OFDM symbol, the related ratematching parameters and quasi-collocation assumption for ePDCCH when theUE is configured in coordinated transmission mode. A coordinatedtransmission mode parameter may provide the index of PDSCH configurationfor coordinated transmission mode.

In another example embodiment, the same RRC message may configurecell(s) and ePDCCH in the downlink of the cell. The RRC message causingthe configuration of carriers (cells) in the wireless device maycomprise an identifier for a carrier in the plurality of carriers,information identifying a carrier type for each carrier in the pluralityof carriers, and information associating at least one non-backwardcompatible carrier (NCT) with a backward compatible carrier. The controlmessage may further comprise information associating a non-backwardcompatible carrier with a backward compatible carrier. Carrier type forexample may be backward compatible, non-backward compatible. The carriertype may further determine if the carrier is synchronized,non-synchronized, and/or a segment carrier. The carrier type maydetermine if the non-backward compatible carrier is a stand-alonecarrier or depends on (is associated with) another carrier. The carriertype information may be transmitted explicitly by a carrier typeparameter, or may be determined based one or more parameters in the RRCmessage(s).

According to some of the various aspects of embodiments, an ePDCCH maycarry scheduling assignments for uplink and downlink of one or morecells. Scheduling assignments includes transmission format (modulationand coding) and resource assignment information. The base station maytransmit first transmission format and scheduling information by thebase station on an ePDCCH in a first subframe of the subset ofsubframes. The first transmission format and the scheduling informationmay be for one or more first data packets (transport blocks) transmittedon a data channel of the first carrier. The base station may transmitthe one or more first data packets to the wireless device on the firstdata channel in the first subframe according to the transmission formatand the scheduling information.

According to some of the various aspects of embodiments, an ePDCCH of afirst carrier may provide scheduling assignment for transport blocks(packets) transmitted on uplink data channel and downlink data channelof the first carrier. Cross carrier scheduling may be configured byhigher layers (e.g., RRC), for example, for a second carrier. The ePDCCHof a first carrier may also provide scheduling assignment for transportblocks (packets) transmitted on uplink data channel and downlink datachannel of the second carrier. ACK/NACK for packets transmitted in thedownlink (according to ePDCCH assignment) may be provided in PUCCHresources identified by the corresponding uplink control channelparameter (in RRC message). ACK/NACK may also be piggybacked and betransmitted in uplink transport blocks transmitted in the uplink sharedchannel. ACK/NACK for packets transmitted in the uplink (according toePDCCH assignment) may be provided in the downlink employing physicalHARQ indicator channel of the first carrier. Radio resourceconfiguration of physical HARQ indicator channel of the first carriermay be determined according to master information block transmitted inPBCH, or may be transmitted by higher layers (e.g. RRC) when the firstcarrier is configured. HARQ radio resources (symbol(s), subcarrier(s))transmitting ACK/NACK for an uplink packet scheduled by ePDCCHassignment may be determined according to a physical resource blockoffset of the uplink resources. For example, a pre-defined relationship(e.g. look-up table, formula, relationship) may determine downlink HARQresources for an uplink packet transmitted on physical uplink sharedchannel.

According to some of the various aspects of embodiments, ePDCCHresources may be configured for one or more carriers in one or moreconfigured carriers for a wireless device. For example, ePDCCH may beconfigured for at least one of a primary carrier, a secondary carrier, abackward-compatible carrier or a non-backward compatible carrier. In anexample embodiment, the starting symbol of ePDCCH and PDSCH for aprimary carrier or for a backward-compatible secondary carrier may beone of the second, third, fourth symbol, or fifth symbol (respectivelycorresponding to symbol 1, 2, 3, 4). In another example, the startingsymbol of ePDCCH and PDSCH for a non-back-ward compatible secondarycarrier may be one of the first, second, third, fourth symbol, or fifthsymbol (respectively corresponding to symbol 0, 1, 2, 3, 4). At leastthe first symbol in a primary carrier or in a backward compatiblesecondary carrier is allocated to legacy PCFICH, legacy PDCCH and legacyHARQ channels. In a non-backward compatible secondary carrier legacyPCFICH, legacy PDCCH and/or legacy HARQ channels may be avoided as awhole in the carrier. This may increase spectral efficiency ofnon-backward compatible carriers compared with backward compatiblecarriers.

According to some of the various aspects of embodiments, an ePDCCH maybe transmitted on a backward compatible or non-backward compatiblecarrier. The ePDCCH may not be transmitted in certain subframes, e.g.,subframes configured with multicast transmission and some TDD specialsubframes. Physical multicast channel (PMCH) may occupy all resourceblocks of a carrier. RRC message(s) may cause configuration of thesubset of subframes in which a UE may monitor ePDCCH. If one theconfigured ePDCCH subframes overlaps with a PMCH subframe, the UE maymonitor UE-specific search space on PDCCH of the subframe and may notsearch ePDCCH resources on a subframe with configured PMCH transmission.In new carrier types, PDCCH may be configured for a subset of subframes.If legacy control region is configured on a new carrier type, areference signal transmitted in the control radio resource region may beused to demodulate the legacy control channel.

According to some of the various aspects of embodiments, legacy downlinkcontrol channels may be configured for subframes with configured PMCH.The subframes that are configured with PMCH may be configured withPDCCH, PCFICH, and/or PHICH. PDCCH resources in PMCH may be employed forscheduling uplink packets in an uplink subframe. This may increaseuplink spectral efficiency in a new type carrier. In another exampleembodiment, configuration parameters of PDCCH may be included in the RRCmessage configuring the new carrier type. PDCCH configuration parametersmay include at least: subframe configuration, and/or PDCCH duration.Subframe configuration parameters for example could be in the form of abitmap. For example a bitmap with length of 40 bits may indicate thesubset of subframes with configured PDCCH with a period of 4 frames. Inanother example embodiment, a subframe index and a subframe period maybe used to determine the subset of subframes with a configured PDCCH. APDCCH may occupy one, two, three or four symbols. PDCCH durationparameter in RRC message may indicate the number of symbols allocated into PDCCH. In another example embodiment, subframe configurationparameter in the RRC message may indicate the subset of subframes withconfigured PCFICH, and PDCCH configuration. PCFICH in each subframe maydetermine the duration of PCFICH in the same subframe. In anotherexample embodiment, subframe configuration parameter in the RRC messagemay indicate the subset of subframes with configured with PCFICH, PDCCH,and PHICH. PHICH radio resources may be employed for transmission ofACK/NACK in the downlink for packets transmitted in the uplink.

According to some of the various aspects of embodiments, RRC message(s)may configure cross carrier scheduling for a new type carrier. RRCmessage may configure cross carrier scheduling for a subset ofsubframes. The cross carrier scheduling configuration parameters maycomprise a bitmap indicating the subset of subframes that cross carrierscheduling is configured for a new type carrier. For example, crosscarrier scheduling may be configured for subframes including PMCHtransmission. In non-PMCH subframes, the ePDCCH of the same carrier maybe used for scheduling assignments. In PMCH subframes, the ePDCCH orPDCCH of another carrier may be employed for uplink packet assignment ofthe carrier employing cross carrier scheduling.

According to some of the various aspects of embodiments, new type (alsocalled non-backward compatible or non-prime) carriers may be configuredto work in association with another backward compatible carrier. Newcarrier types may be deployed in heterogeneous networks and/orhomogeneous networks, and may coexist with backward compatible carriersin the same base station/sector. In another example embodiment, newcarrier types may be configured on standalone bases without backwardcompatible carriers. New type carriers may have reduced legacy controlsignalling and common reference signals. The interference and overheadlevels on the new carrier types may be reduced compared to backwardcompatible carriers. A new carrier type may be synchronized with anothercarrier in the same band. In another example embodiment, a new carriertype may not be synchronized with another carrier.

New carrier types may transmit reduced or no common reference signalcompared with backward compatible carriers. In one example embodiment,new carrier type may carry one reference signal port (for example,common reference signal port 0 resource elements per physical resourceblock) and may employ legacy common reference signal sequences. Commonreference signals may be transmitted within one subframe with five msperiodicity. In this example, two of the ten subframes in a frame maytransmit common reference signals. The common reference signal may beemployed by the wireless device for example, for channel statemeasurement, time and/or frequency synchronization, receiver parameterestimation, and/or the like. Common reference signal may be transmittedon all resource blocks in the bandwidth or in a subset of resourceblock. In an example embodiment, the bandwidth of common referencesignal may be configured by higher layers (e.g. RRC layer). For example,common reference signal may be transmitted on 6 resource blocks or 25resource blocks according to RRC configuration. RRC configurationparameters for example may include at least one of: configuration ofcommon reference subframes (e.g. subframe index, periodicity, and/orbitmap configuration), frequency resources (common reference signalbandwidth, frequency offset, and/or frequency shift in resource blocks).In an example embodiment a subframe bitmap parameter may indicate thesubset of subframes transmitting common reference signals. In an exampleembodiment, a resource block bitmap parameter may indicate the resourceblocks transmitting common reference signals. Configuration of commonreference signal may consider that the reduced common reference signalmay impact the time and frequency synchronization performance and radioresource monitoring measurements. In an example embodiment, commonreference signal may be transmitted in the same subframe as the primaryand secondary synchronization signals. In another example embodiment, asubframe offset parameter may be configured by higher layers (e.g. RRC).A cell-specific frequency shift may be used for common referencesignals. The motivation of frequency shift is to reduce common referencesignal collision among neighbouring cells. In an example embodiment, thefrequency shift may be determined by the physical cell identifier. Inanother example embodiment, frequency shift may be configured employingconfiguration parameters comprised in RRC messages configuring a newtype carrier.

According to some of the various aspects of embodiments, a new typecarrier may be configured as a synchronized carrier. The UE may beconfigured to acquire time and frequency synchronization from a backwardcompatible carrier to which the synchronized carrier is associated with.In an example embodiment, RRC message(s) configuring the new typecarrier may comprise the carrier index of the backward compatiblecarrier associated with the new type carrier. The synchronized andnon-synchronized carrier may include reduced CRS transmissionconfigurable by parameters comprised in an RRC message. In an exampleembodiment, a synchronized carrier may be configured to not transmit anycommon reference signals and/or synchronization signals.

According to some of the various aspects of embodiments, primary andsecondary signals may be transmitted on a non-synchronized carrier. Theprimary and secondary synchronization signals may be transmitted in thecentre six resource blocks of a carrier. The time location of theprimary and secondary synchronization signal may be configured using RRCmessage configuring the new type carrier. In an example configuration ofa new carrier type, there may be collisions between radio resource ofprimary/secondary synchronization signals and demodulation referencesignals. To resolve this issue, demodulation reference signals may notbe transmitted when it overlaps with the synchronization signals. In anexample embodiment, primary and secondary synchronization signals maynot be transmitted on a synchronized new carrier type. This may reducesignalling overhead and increase spectral efficiency. An RRC messageconfiguring a new type carrier may provide configuration parameters forprimary and secondary synchronization signals and/or may indicatewhether primary and/or secondary synchronization signals are transmittedor not.

New carrier types may support existing and/or new transmission modescompared with backward compatible carrier. RRC layer may provideinformation to the UE indicating which transmission modes are employedfor transmission of transport blocks on a new carrier type. According tosome of the various aspects of embodiments, sounding referenceconfiguration for backward compatible carriers may be improved toinclude the capability of transmitting sounding reference signal on allactive uplink resource blocks of a carrier. In legacy sounding referencesignal configuration, sounding reference signal may not be transmittedon resource blocks of PUCCH radio resources in the uplink. Soundingreference signal configuration may be improved to include all resourceblocks employed for PUSCH (including resource blocks employed for PUCCHin legacy carrier, which are available for PUSCH in new type carriers).The SRS bandwidth may be chosen assuming that all active RBs in theuplink may be used for PUSCH. Then eNB may be able to sound any resourceblock usable for PUSCH transmission.

FIG. 5 is a diagram depicting time and frequency resources for carrierone 501 and carrier two 502 and FIG. 6 is a diagram illustratingtransmission of data and control information according to one aspect ofthe illustrative embodiments. An example embodiment of the inventionprovides a method and system for a wireless transmitter in acommunication network including a plurality of carriers. Each of theplurality of carriers may include a plurality of OFDM subcarriers.Transmission time may be divided into a plurality of subframes, and eachsubframe in the plurality of subframes may further be divided into aplurality of OFDM symbols.

The transmitter may transmit a synchronization signal including aprimary synchronization signal and a secondary synchronization signal ona first carrier 501. The synchronization signal may indicate a physicalcell ID for the first carrier 501. It may also provide timinginformation for the first carrier 501 and a second carrier 502 in theplurality of carriers. The synchronization signal may be transmittedusing a plurality of subcarriers in the in the middle of the frequencyband of the first carrier 501 on the first and sixth subframes (subframe0 and 5) of each frame in the plurality of frames. Primary and secondarysynchronization signal may occupy a bandwidth equal to six resourceblocks. A physical broadcast channel (PBCH) 505 may be transmitted inslot one 504 of subframe 0 of the first carrier 501.

The transmitter may transmit a first plurality of data packets on afirst data channel 603 of the first carrier 606 on a first plurality ofOFDM subcarriers. A first plurality of OFDM subcarriers may exclude theplurality of subcarriers used for transmission of the primary andsecondary synchronization signals in the first and sixth subframes inthe plurality of frames.

The transmitter may transmit a first plurality of broadcast systeminformation messages on the first data channel 603. The plurality ofbroadcast system information messages include radio link configurationinformation for a wireless device receiving the first carrier 606 andthe second carrier 607 signals.

The transmitter may transmit a second plurality of data packets on asecond data channel 605 on a second plurality of OFDM subcarriers of thesecond carrier 607.

The second plurality of OFDM subcarriers of the second carrier 502 mayinclude the OFDM subcarriers in the middle of the frequency band of thesecond carrier 502 in the first and sixth subframes in the plurality offrames. No primary synchronization signal and no secondarysynchronization signal may be transmitted on the second carrier in radioresource. No broadcast system information message may be transmitted onthe second data channel 605. No physical broadcast channel may betransmitted in radio resource 506. Subframe timing of the second datachannel is provided by the synchronization signal transmitted on thefirst carrier. Multiple options may be available, for example secondcarrier may transmit synchronization signal but do not transmit thephysical broadcast channel. In another example, both carriers maytransmit both synchronization signal and physical broadcast channel.

The first plurality of data packets and the second plurality of datapackets may be transmitted using a plurality of physical resource blocksincluding reference signal symbols and data symbols. The broadcastsystem information messages may be RRC system information blocks. Theradio link configuration information may include measurementconfiguration, uplink channel configuration or handover parameters.

The primary synchronization signal may be generated using afrequency-domain Zadoff-Chu sequence. The primary synchronization signalmay be mapped to the last OFDM symbol in slots zero and ten for FDDframe structure. The primary synchronization signal may be mapped to thethird OFDM symbol in subframes 1 and 6 for TDD frame structure.

The secondary synchronization signal may be generated using aninterleaved concatenation of two length-31 binary sequences. Theconcatenated sequence may be scrambled with a scrambling sequence givenby the primary synchronization signal. The portion of the secondarysynchronization signal transmitted in subframe zero may be differentfrom the portion of the secondary synchronization signal transmitted insubframe five.

A control channel 602 may be transmitted on the first carrier 606. Thecontrol channel 602 may provide transmission format and schedulinginformation for the first plurality of data packets and the secondplurality of data packets. The control channel 602 may be transmitted onthe first carrier 606 starting from the first OFDM symbol of eachsubframe. The control channel may be a physical downlink controlchannel. No physical control format indicator channel and no physicaldownlink control channel may be transmitted on the second carrier 607.Radio resources of the second data channel 605 may start from the firstOFDM symbol of each subframe of the second carrier 607 and end at thelast OFDM symbol of each subframe of the second carrier 607. No HARQfeedback may be transmitted on the second carrier 607. Subframe timingof the second carrier 607 may be synchronized with subframe timing ofthe first carrier 606.

Another example embodiment of the present invention provides a methodand system for a wireless receiver in a communication network includinga plurality of carriers. Each of the plurality of carriers may include aplurality of OFDM subcarriers. Reception time may be divided into aplurality of subframes. Each subframe in the plurality of subframes mayfurther be divided into a plurality of OFDM symbols.

The receiver may receive a synchronization signal including a primarysynchronization signal and a secondary synchronization signal on a firstcarrier 501. The synchronization signal may indicate a physical cell IDfor the first carrier. It may also provide timing information for thefirst carrier 501 and a second carrier 502 in the plurality of carriers.The synchronization signal may be received using a plurality ofsubcarriers in the in the middle of the frequency band of the firstcarrier 501 on the first and sixth subframes (subframe 0 and 5) of eachframe in the plurality of frames. A physical broadcast channel (PBCH)505 may be received in slot one 504 of subframe 0 of the first carrier501.

The receiver may receive a first plurality of data packets on a firstdata channel 603 of the first carrier 606 on a first plurality of OFDMsubcarriers. A first plurality of OFDM subcarriers may exclude theplurality of subcarriers used for transmission of the primary andsecondary synchronization signals in the first and sixth subframes inthe plurality of frames.

The receiver may receive a first plurality of broadcast systeminformation messages on the first data channel 603. The plurality ofbroadcast system information messages may include radio linkconfiguration information for the wireless receiver receiving the firstcarrier 606 and the second carrier 607 signals.

The receiver may receive a second plurality of data packets on a seconddata channel 605 on a second plurality of OFDM subcarriers of the secondcarrier 607. The second plurality of OFDM subcarriers of the secondcarrier 607 may include the OFDM subcarriers in the middle of thefrequency band of the second carrier 502 in the first and sixthsubframes in the plurality of frames. No primary synchronization signaland no secondary synchronization signal may be received on the secondcarrier in radio resource. No broadcast system information message maybe received on the second data channel 605. No physical broadcastchannel may be received in radio resource 506. Subframe timing of thesecond data channel may be provided by the synchronization signalreceived on the first carrier.

The first plurality of data packets and the second plurality of datapackets are received using a plurality of physical resource blocksincluding reference signal symbols and data symbols. The broadcastsystem information messages may be RRC system information blocks. Theradio link configuration information may include measurementconfiguration, uplink channel configuration, or handover parameters.

The primary synchronization signal may be generated using afrequency-domain Zadoff-Chu sequence. The primary synchronization signalmay be mapped to the last OFDM symbol in slots zero and ten for FDDframe structure. The primary synchronization signal may be mapped to thethird OFDM symbol in subframes 1 and 6 for TDD frame structure.

The secondary synchronization signal may be generated using aninterleaved concatenation of two length-31 binary sequences. Theconcatenated sequence may be scrambled with a scrambling sequence givenby the primary synchronization signal. The portion of the secondarysynchronization signal transmitted in subframe zero may be differentfrom the portion of the secondary synchronization signal transmitted insubframe five.

A control channel 602 is received on the first carrier 606. The controlchannel 602 may provide transmission format and scheduling informationfor the first plurality of data packets and the second plurality of datapackets. The control channel 602 may be received on the first carrier606 starting from the first OFDM symbol of each subframe. The controlchannel 602 may be a physical downlink control channel. No physicalcontrol format indicator channel and no physical downlink controlchannel may be received on the second carrier 607. Radio resources ofthe second data channel 605 may start from the first OFDM symbol of eachsubframe of the second carrier 607 and end at the last OFDM symbol ofeach subframe of the second carrier 607. No HARQ feedback may bereceived on the second carrier 607. Subframe timing of the secondcarrier 607 may be synchronized with subframe timing of the firstcarrier 606.

FIG. 6 is a diagram illustrating data and control transmission channelsaccording to one aspect of the illustrative embodiments. An exampleembodiment of the present invention provides a method and system for awireless transmitter in a communication network including a plurality ofcarriers. Each of the plurality of carriers may include a plurality ofOFDM subcarriers. Transmission time may be divided into a plurality ofsubframes, and each subframe in the plurality of subframes may furtherbe divided into a plurality of OFDM symbols.

The transmitter may transmit a first control channel 601 on the firstOFDM symbol of each subframe 608 in the plurality of subframes of afirst carrier 606 in the plurality of carriers. Each instance of thefirst control channel 601 transmitted in a subframe 608 in the pluralityof subframes may indicate the number of OFDM symbols in the subframethat are preferably allocated for transmission of a second controlchannel 602 on the subframe 608 of the first carrier 606.

The transmitter may transmit the second control channel 602 on the firstcarrier 606. The second control channel 602 may provide transmissionformat and scheduling information for a first plurality of data packetstransmitted on a first data channel 603 of the first carrier 606. Thesecond control channel 602 may be transmitted on the first carrier 606starting from the first OFDM symbol of the subframe 608. A subset ofOFDM subcarriers of the first symbol of each subframe is used by thefirst control channel, and a second subset of OFDM subcarriers of thefirst symbol of each subframe is used by the second control channel.

The transmitter may transmit the first plurality of data packets on thefirst data channel 603. The first data channel transmission may startfrom the OFDM symbol immediately after the number of OFDM symbolsallocated for the second control channel 602. For example in a givensubframe, the first, second and third symbols are used by the first andsecond control channel, and the forth to fourteenth symbols are used bythe first data channel.

The transmitter may transmit a control message 604 on the first datachannel 603 indicating that radio resources of a second data channel 605start from the first OFDM symbol of each subframe of a second carrier607 in the plurality of carriers. The control message may furtherindicate that the second control channel 602 includes transmissionformat and scheduling information for a second plurality of data packetstransmitted on the second data channel 605 of the second carrier 607.The control message 604 may be transmitted only once or only when theradio configuration changes. The control message 604 may not betransmitted in every subframe.

The transmitter may transmit the second plurality of data packets on thesecond data channel 605. Radio resources for the second data channel 605may start from the first OFDM symbol and end at the last OFDM symbol ofeach subframe 608 of the second carrier 607. The transmission format andscheduling information for the second plurality of data packets may betransmitted on the second control channel 602 of the first carrier 606.

Synchronization signal may be transmitted in subframes 0 and 5 in themiddle of the band 609 on carrier one. Synchronization signal is nottransmitted in carrier two 607. Instead the same resource may beallocated to the second data channel 605.

In another example embodiment of this invention, the transmitter maytransmit a control channel 602 on a first carrier 606 in the pluralityof carriers. The second control channel 602 may provide transmissionformat and scheduling information for a first plurality of data packetstransmitted on a first data channel 603 of the first carrier 606.

The transmitter may transmit a control message 604 on the first datachannel indicating that radio resources of a second data channel 605start from the first OFDM symbol of each subframe of a second carrier607 in the plurality of carriers. The control message 604 may furtherindicate that the second control channel 602 includes transmissionformat and scheduling information for a second plurality of data packetstransmitted on the second data channel 605.

The transmitter transmit the second plurality of data packets on thesecond data channel 605. Radio resources for the second data channel 605may start from the first OFDM symbol and end at the last OFDM symbol ofeach subframe 608 of the second carrier. The transmission format andscheduling information for the second plurality of data packets may betransmitted on the second control channel 602 of the first carrier 606.

The first control channel 601 may be transmitted on a first subset ofthe plurality of OFDM subcarriers of the first carrier 606. Eachinstance of the first control channel 601 may indicate one of threepossible values after being decoded. The range of possible values ofeach instance of the first control channel may depend on many parametersincluding the first carrier bandwidth. For example for a givenbandwidth, the first control channel may indicate of three possiblevalues of 1, 2, or 3 symbols. The first control channel 601 istransmitted on the first OFDM symbol of each subframe 608 of the firstcarrier 606 using QPSK modulation. The first control channel 601 may becoded using a block encoder before transmission. The first controlchannel 601 may be scrambled by a transmitter ID before transmission.The transmitter ID may be for example the physical cell ID.

The second control channel 602 may be transmitted on a second subset ofthe plurality of OFDM subcarriers of the first carrier 606. The secondcontrol channel 602 may be transmitted using QPSK modulated symbols. Thesecond control channel 602 may be coded by tail biting convolutionallyencoder before transmission. The second control channel 602 may furtherprovide power control commands for uplink channels, for example powercontrol commands for physical uplink shared channel or physical uplinkcontrol channel. The OFDM subcarriers that are allocated fortransmission of the second control channel 602 may occupy the entirebandwidth of the first carrier 606. The second channel may not use theentire subcarriers allocated to it. The second control channel 602 maycarry a plurality of downlink control packets in each subframe 608 inthe plurality of subframes. Each of the plurality of downlink controlpackets may be scrambled using a radio network identifier.

The first plurality of data packets and the second plurality of datapackets may be encrypted packets. Each of the first plurality of datapackets and each of the second plurality of data packets may be assignedto a radio bearer. A first plurality of packets that are assigned to thesame radio bearer may be encrypted using an encryption key and at leastone parameter that changes substantially rapidly over time.

The control message 604 may be encrypted and may be protected by anintegrity header before it is transmitted. The control message 604 maybe transmitted by an RRC protocol. The control message 604 may furtherinclude configuration information for physical channels for a wirelessterminal. The control message 604 may set up or modify at least oneradio bearer. The control message 604 may modify configuration of atleast one parameter of a MAC layer or a physical layer. The controlmessage 604 may be an RRC connection reconfiguration message.

No physical control channel may be transmitted on the second carrier607. No HARQ feedback may be transmitted on the second carrier 607.Subframe timing of the second carrier 607 may be preferably synchronizedwith subframe timing of the first carrier 606.

Another example embodiment of the invention provides a method and systemfor a wireless receiver in a communication network including a pluralityof carriers. Each of the plurality of carriers may include a pluralityof OFDM subcarriers. Reception time may be divided into a plurality ofsubframes 602. Each subframe 202 in the plurality of subframes mayfurther be divided into a plurality of OFDM symbols 203.

The receiver may receive a first control channel 601 on the first OFDMsymbol of each subframe 608 in the plurality of subframes of a firstcarrier 606 in the plurality of carriers. Each instance of the firstcontrol channel 601 received in a subframe 608 in the plurality ofsubframes may indicate the number of OFDM symbols in the subframe thatare allocated for reception of a second control channel 602 on thesubframe of the first carrier 606.

The receiver may receive the second control channel 602 on the firstcarrier 606. The second control channel 602 may provide reception formatand scheduling information for a first plurality of data packetsreceived on a first data channel 603 of the first carrier 606. Thesecond control channel 602 may be received on the first carrier 606starting from the first OFDM symbol of the subframe 608. A subset ofOFDM subcarriers of the first symbol of each subframe is used by thefirst control channel, and a second subset of OFDM subcarriers of thefirst symbol of each subframe is used by the second control channel.

The receiver may receive the first plurality of data packets on thefirst data channel 603. The first data channel reception may start fromthe OFDM symbol immediately after the number of OFDM symbols allocatedfor the second control channel 602. For example in a given subframe, thefirst, second and third symbols are used by the first and second controlchannel, and the forth to fourteenth symbols are used by the first datachannel.

The receiver may receive a control message 604 on the first data channel603 indicating that radio resources of a second data channel 605 startfrom the first OFDM symbol of each subframe of a second carrier 607 inthe plurality of carriers. The control message may further indicate thatthe second control channel 602 includes reception format and schedulinginformation for a second plurality of data packets received on thesecond data channel 605 of the second carrier 607. The control message604 may be received only once or only when the radio configurationchanges. The control message 604 may not be received in every subframe.

The receiver may receive the second plurality of data packets on thesecond data channel 605. Radio resources for the second data channel 605may start from the first OFDM symbol and end at the last OFDM symbol ofeach subframe 608 of the second carrier 607. The reception format andscheduling information for the second plurality of data packets may bereceived on the second control channel 602 of the first carrier 606.

In another example embodiment of this invention, the wireless receivermay receive a second control channel 602 on a first carrier 606 in theplurality of carriers. The second control channel 602 may providereception format and scheduling information for a first plurality ofdata packets received on a first data channel 603 of the first carrier606.

The receiver may receive a control message 604 on the first data channelindicating that radio resources of a second data channel 605 start fromthe first OFDM symbol of each subframe of a second carrier 607 in theplurality of carriers. The control message 604 may further indicate thatthe second control channel 602 includes reception format and schedulinginformation for a second plurality of data packets received on thesecond data channel 605.

The receiver may receive the second plurality of data packets on thesecond data channel 605. Radio resources for the second data channel 605may start from the first OFDM symbol and end at the last OFDM symbol ofeach subframe 608 of the second carrier. The reception format andscheduling information for the second plurality of data packets may bereceived on the second control channel 602 of the first carrier 606.

The first control channel 601 may be received on a first subset of theplurality of OFDM subcarriers of the first carrier 606. Each instance ofthe first control channel 601 may indicate one of three possible valuesafter being decoded. The range of possible values of each instance ofthe first control channel may depend on many parameters including thefirst carrier bandwidth 606. For example for a given bandwidth, thefirst control channel may indicate of three possible values of 1, 2, or3 symbols. The first control channel 601 may be received on the firstOFDM symbol of each subframe 608 of the first carrier 606 using QPSKdemodulation. The first control channel 601 may be decoded using a blockdecoder after being received. The first control channel 601 may bede-scrambled using a receiver ID after being received. The transmitterID may be for example the physical cell ID.

The second control channel 602 may be received on a second subset of theplurality of OFDM subcarriers of the first carrier 606. The secondcontrol channel 602 may be received using QPSK demodulation of OFDMsymbols. The second control channel 602 may be decoded by tail bitingconvolutionally decoder after being received. The second control channel602 may further provide power control commands for uplink channels, forexample power control commands for physical uplink shared channel orphysical uplink control channel. The OFDM subcarriers that are allocatedto the second control channel 602 may occupy the entire bandwidth of thefirst carrier 606. The second channel may not use the entire subcarriersallocated to it. The second control channel 602 may carry a plurality ofdownlink control packets in each subframe 608 in the plurality ofsubframes. Each of the plurality of downlink control packets may bedescrambled using a radio network identifier.

The first plurality of data packets and the second plurality of datapackets may be encrypted packets. Each of the first plurality of datapackets and each of the second plurality of data packets may be assignedto a radio bearer. A first plurality of packets that are assigned to thesame radio bearer may be decrypted using a decryption key and at leastone parameter that changes substantially rapidly over time.

The control message 604 may be decrypted and its integrity header may beverified before being processed. The control message 604 may be receivedby an RRC protocol. The control message 604 may further includeconfiguration information for physical channels for the wirelessterminal. The control message 604 may set up or modify at least oneradio bearer. The control message 604 may modify configuration of atleast one parameter of a MAC layer or a physical layer. The controlmessage 604 may be an RRC connection reconfiguration message.

No physical control channel may be received on the second carrier 607.No HARQ feedback may be received on the second carrier 607. Subframetiming of the second carrier 607 may be synchronized with subframetiming of the first carrier 606.

In an example embodiment, non-prime carrier (equally called non-backwardcompatible carrier) may include ePDCCH resources. ePDCCH is enhancedphysical downlink control channel and may act as PDCCH for the non-primecarrier. ePDCCH may carry scheduling information for downlink and uplinkshared channels and may also carrier power control information foruplink transmissions.

According to some of the various embodiments, a base station in acommunication network may receive from a wireless device a first channelstate information. The first channel state information may comprise afirst precoding matrix identifier. The first channel state informationmay additionally include CQI and RI. The base station may transmit tothe wireless device one or more data packets on a data channel employingthe first precoding matrix identifier. The base station may transmit oneor more control packets on a control channel to the wireless deviceemploying a second precoding matrix. The second precoding matrix may becomputed based, at least in part, on the first channel stateinformation. The one or more control packets may carry schedulinginformation for the data channel.

The first precoding matrix identifier may be an index of a precodingmatrix in a precoding codebook. The first precoding matrix identifiermay be obtained at the wireless device based on maximizing a qualitymetric such as signal power, signal to noise ratio, signal to noise andinterference ratio, channel capacity or achievable data rate, etc. Thecontrol channel may be transmitted on a subset of antennas ports, andemploying a subset of layers used for data transmission. The basestation may compute the second precoding matrix based on a submatrix ofa first precoding matrix identified by the first precoding matrixidentifier. The control channel may be transmitted on a number ofvirtual antennas that are formed by applying a linear processing onphysical antennas. The base station may use a linear transformation on asubset of rows and columns of the first precoding matrix to obtain thesecond precoding matrix. The linear transformation used to derive thesecond precoding matrix from the first precoding matrix may be afunction of the linear processing used to form virtual antennas forcontrol channel transmission. The base station may use other forms oftransformation on a subset of rows and columns of the first precodingmatrix to obtain the second precoding matrix.

According to some of the various embodiments, a base station maytransmit to a wireless device channel state information referencesignals. The base station may receive from the wireless device a firstchannel state information. The first channel state information maycomprise a first precoding matrix identifier. The first channel stateinformation may be computed employing the channel state informationreference signals. The base station may transmit to the wireless devicefirst downlink signals employing the first precoding matrix identifier.The first downlink signals may comprise one or more data packets andfirst demodulation reference signals. The one or more data packets maybe transmitted on a data channel. The first demodulation referencesignals may be used to demodulate the one or more data packets. The basestation may transmit to the wireless device second downlink signalsemploying a second precoding matrix. The second downlink signals maycomprise one or more control packets and second demodulation referencesignals. The one or more control packets may be transmitted on a controlchannel. The second demodulation signals may be used to demodulate theone or more control packets. The second precoding matrix may be computedbased, at least in part, on the first channel state information. The oneor more control packets may carry scheduling information for the datachannel.

The channel state reference signal may be transmitted on the antennaports used for transmission of the one or more data packets on the datachannel. The channel state reference signal may be transmitted on theantenna ports used for transmission of the one or more control packetson the control channel. The channel state information reference signalmay be transmitted on both antenna ports used for transmission of theone or more data packets on the data channel and antenna ports used fortransmission of the one or more control packets on the control channel.The channel state information reference signals may be used by thewireless device for channel estimation. The wireless device may obtainthe first precoding matrix identifier by computing a quality metric foreach candidate precoding matrix from the precoding codebook andselecting the identifier of the candidate precoding matrix that resultsin the largest quality metric. The wireless device may combine thecandidate precoding matrix with the estimated channel matrix to obtain acomposite channel matrix. The wireless device may use the compositechannel matrix to compute the quality metric corresponding to eachcandidate precoding matrix.

According to some of the various embodiments, a base station maycomprise a plurality of carriers. Each of the plurality of carriers maycomprise a plurality of OFDM subcarriers. Transmission time may bedivided into a plurality of frames. Each frame in the plurality offrames may be further divided into a plurality of subframes. The basestation may transmit to a wireless device channel state informationreference signals on a first plurality of OFDM subcarriers of a firstplurality of OFDM symbols of a first subset of subframes. The basestation may receive from the wireless device a first channel stateinformation. The first channel state information may comprise a firstprecoding matrix identifier. The first channel state information may becomputed employing the channel state information reference signals. Thebase station may transmit to the wireless device first downlink signalson a second plurality of OFDM sub carriers of a second plurality of OFDMsymbols of a subframe employing the first precoding matrix identifier.The first downlink signals may comprise one or more data packets andfirst demodulation reference signals. The one or more data packets maybe transmitted on a data channel. The first demodulation referencesignals may be used to demodulate the one or more data packets. The basestation may transmit to the wireless device second downlink signals on athird plurality of OFDM subcarriers of a third plurality of OFDM symbolsof the subframe employing a second precoding matrix. The second downlinksignals may comprise one or more control packets and second demodulationreference signals. The one or more control packets may be transmitted ona control channel. The second demodulation reference signals may be usedto demodulate the one or more control packets. The third plurality ofOFDM subcarriers may be different from the second plurality of OFDMsubcarriers or the third plurality of OFDM symbols may be different fromthe second plurality of OFDM symbols. The second precoding matrix may becomputed based, at least in part, on the first channel stateinformation. The one or more control packets may carry schedulinginformation for packets transmitted on the data channel. The controlchannel may carry scheduling information for the data channel.

According to some of the various embodiments, the first demodulationreference signals and the second demodulation reference signals may betransmitted on different antenna ports. The second demodulationreference signals may be transmitted employing a smaller number ofantenna ports than the first demodulation reference signals. The secondprecoding matrix may have smaller number of columns than the firstprecoding matrix. The second precoding matrix may use smaller number ofMIMO layers than the first precodoing matrix. The second precodingmatrix may be a submatrix of the first precoding matrix. The secondprecoding matrix may be a column vector. The second demodulationreference signals may be transmitted from a single antenna port. Thesecond demodulation reference signals may be transmitted from twoantenna ports. The second demodulation reference signals may comprise atleast two orthogonal reference signals. The one or more control packetsmay be transmitted employing multi-user MIMO. The base station maytransmit one or more second control packets to a second wireless deviceemploying the third plurality of OFDM subcarriers of said thirdplurality of OFDM symbols of the subframe. The transmission of the oneor more second control packets to the second wireless device employingthe third plurality of OFDM subcarriers of the third plurality of OFDMsymbols of the subframe may use a third precoding matrix.

According to some of the various embodiments, a base station may receivefrom a wireless device a first channel state information for a datachannel. The first channel state information may comprise a firstprecoding matrix identifier. The base station may receive from thewireless device a second channel state information for a controlchannel. The second channel state information may comprise a secondprecoding matrix identifier. The base station may transmit to thewireless device one or more data packets on the data channel employingthe first precoding matrix identifier. The base station may transmit tothe wireless device one or more control packets on the control channelemploying the second precoding matrix identifier. The one or morecontrol packets may carry scheduling information for the data channel.

The first precoding matrix identifier may be an index of a firstprecoding matrix in a first precoding codebook. The first precodingmatrix identifier may be obtained at the wireless device based onmaximizing a quality metric such as signal power, signal to noise ratio,signal to noise and interference ratio, channel capacity or achievabledata rate, etc. The second precoding matrix identifier may be an indexof a second precoding matrix in a second precoding codebook. The secondprecoding matrix identifier may be obtained at the wireless device basedon maximizing a quality metric such as signal power, signal to noiseratio, signal to noise and interference ratio, channel capacity orachievable data rate, etc. The one or more control packets may betransmitted on a subset of antennas ports, and employing a subset oflayers used for data transmission. The one or more control packets maybe transmitted on a number of virtual antennas that are formed byapplying a linear processing on physical antennas.

According to some of the various embodiments, a base station maytransmit to a wireless device channel state information referencesignals. The base station may receive from the wireless device a firstchannel state information for a data channel. The first channel stateinformation may comprise a first precoding matrix identifier. The firstchannel state information may be computed employing the channel stateinformation reference signals. The base station may receive from thewireless device a second channel state information for a controlchannel. The second channel state information may comprise a secondprecoding matrix identifier. The second channel state information may becomputed employing the channel state information reference signals. Thebase station may transmit to the wireless device first downlink signalsemploying the first precoding matrix identifier. The first downlinksignals may comprise one or more data packets and first demodulationreference signals. The one or more data packets may be transmitted onthe data channel. The first demodulation reference signals may be usedto demodulate the one or more data packets. The base station maytransmit to the wireless device second downlink signals employing thesecond precoding matrix identifier. The second downlink signals maycomprise one or more control packets and second demodulation referencesignals. The one or more control packets may be transmitted on thecontrol channel. The second demodulation reference signals may be usedto demodulate the one or more control packets. The one or more controlpackets may carry scheduling information for the data channel.

The channel state information reference signals may be transmitted onthe antenna ports used for transmission of the one or more data packets.The channel state information reference signals may be transmitted onthe antenna ports used for transmission of the one or more controlpackets. The channel state information reference signals may betransmitted on both antenna ports used for transmission of the one ormore data packets and antenna ports used for transmission of the one ormore control packets. The channel state information reference signalsmay be used by the wireless device for channel estimation. The wirelessdevice may estimate a channel matrix for the data channel employing thechannel state information reference signals. The wireless device mayestimate a channel matrix for the control channel employing the channelstate information reference signals. The wireless device may obtain thefirst precoding matrix identifier for the data channel by computing aquality metric for each candidate precoding matrix from the firstprecoding codebook and selecting the identifier of the candidateprecoding matrix that results in the largest quality metric. Thewireless device may combine the candidate precoding matrix with theestimated channel matrix for the data channel to obtain a compositechannel matrix. The wireless device may use the composite channel matrixto compute the quality metric corresponding to each candidate precodingmatrix for the data channel. The wireless device may obtain the secondprecoding matrix identifier for the control channel by computing aquality metric for each candidate precoding matrix from the secondprecoding codebook and selecting the identifier of the candidateprecoding matrix that results in the largest quality metric. Thewireless device may combine the candidate precoding matrix with theestimated channel matrix for the control channel to obtain a compositechannel matrix. The wireless device may use the composite channel matrixto compute the quality metric corresponding to each candidate precodingmatrix for the control channel.

According to some of the various embodiments, a base station maycomprise a plurality of carriers. Each of the plurality of carriers maycomprise a plurality of OFDM subcarriers. Transmission time may bedivided into a plurality of frames. Each frame in the plurality offrames may further be divided into a plurality of subframes. The basestation may transmit to a wireless device channel state informationreference signals on a first plurality of OFDM subcarriers of a firstplurality of OFDM symbols of a first subset of subframes. The basestation may receive from the wireless device a first channel stateinformation for a data channel. The first channel state information maycomprise a first precoding matrix identifier. The first channel stateinformation may be computed employing the channel state informationreference signals. The base station may receive from the wireless devicea second channel state information for a data channel. The secondchannel state information may comprise a second precoding matrixidentifier. The second channel state information may be computedemploying the channel state information reference signals. The basestation may transmit to the wireless device first downlink signals on asecond plurality of OFDM subcarriers of a second plurality of OFDMsymbols of a subframe employing the first precoding matrix identifier.The first downlink signals may comprise one or more data packets andfirst demodulation reference signals The one or more data packets may betransmitted on the data channel. The first demodulation referencesignals may be used to demodulate the one or more data packets. The basestation may transmit to the wireless device second downlink signals on athird plurality of OFDM subcarriers of a third plurality of OFDM symbolsof the subframe employing the second precoding matrix identifier. Thesecond downlink signals may comprise one or more control packets andsecond demodulation reference signals The one or more control packetsmay be transmitted on the control channel. The third plurality of OFDMsubcarriers may be different from the second plurality of OFDMsubcarriers or the third plurality of OFDM symbols may be different fromthe second plurality of OFDM symbols. The second demodulation signalsmay be used to demodulate the one or more control packets. The one ormore control packets may carry scheduling information for the datachannel.

According to some of the various embodiments, a wireless device maytransmit to a base station a first channel state information for a datachannel. The first channel state information may comprise a firstprecoding matrix identifier. The wireless device may transmit to thebase station a second channel state information for a control channel.The second channel state information may comprise a second precodingmatrix identifier. The wireless device may receive from the base stationone or more data packets on the data channel employing the firstprecoding matrix identifier. The wireless device may receive from thebase station one or more control packets on the control channelemploying the second precoding matrix. The one or more control packetsmay carry scheduling information for the data channel.

According to some of the various embodiments, a communication networkmay comprise a plurality of carriers. Each of the plurality of carriersmay comprise a plurality of OFDM subcarriers. Transmission time may bedivided into a plurality of frames. Each frame in the plurality offrames may further be divided into a plurality of subframes. Thewireless device may receive from a base station channel stateinformation reference signals on a first plurality of OFDM subcarriersof a first plurality of OFDM symbols of a first subset of subframes. Thewireless device may transmit to the base station a first channel stateinformation for a data channel. The first channel state information maycomprise a first precoding matrix identifier. The first channel stateinformation may be computed employing the channel state informationreference signals. The wireless device may transmit to the base stationa second channel state information for a data channel. The secondchannel state information may comprise a second precoding matrixidentifier. The second channel state information may be computedemploying the channel state information reference signals. The wirelessdevice may receive from the base station first downlink signals on asecond plurality of OFDM subcarriers of a second plurality of OFDMsymbols of a subframe employing the first precoding matrix identifier.The first downlink signals may comprise one or more data packets andfirst demodulation reference signals The one or more data packets may betransmitted on the data channel. The first demodulation referencesignals may be used to demodulate the one or more data packets. Thewireless device may receive from the base station second downlinksignals on a third plurality of OFDM subcarriers of a third plurality ofOFDM symbols of the subframe employing the second precoding matrixidentifier. The second downlink signals may comprise one or more controlpackets and second demodulation reference signals The one or morecontrol packets may be transmitted on the control channel. The thirdplurality of OFDM subcarriers may be different from the second pluralityof OFDM subcarriers or the third plurality of OFDM symbols may bedifferent from the second plurality of OFDM symbols. The seconddemodulation signals may be used to demodulate the one or more controlpackets. The one or more control packets may carry schedulinginformation for the data channel.

According to some of the various embodiments, the control channel andthe data channel may be transmitted on the same carrier. The controlchannel and the data channel may be transmitted multiplexed in time. Thecontrol channel and the data channel may be transmitted multiplexed infrequency. The control channel and the data channel may be transmittedmultiplexed employing OFDM resources of the same carrier. The firstdemodulation reference signals and the second demodulation referencesignals may be transmitted on different antenna ports. The seconddemodulation reference signals may be transmitted employing a smallernumber of antenna ports than the first demodulation reference signals.The second precoding matrix may have smaller number of columns than thefirst precoding matrix. The second precoding matrix may use smallernumber of MIMO layers than the first precodoing matrix.

The second precoding matrix may be a submatrix of the first precodingmatrix. The second precoding matrix may be a column vector. The seconddemodulation reference signals may be transmitted from a single antennaport. The second demodulation reference signals may be transmitted fromtwo antenna ports. The second demodulation reference signals maycomprise at least two orthogonal reference signals. The one or morecontrol packets may be transmitted employing multi-user MIMO. One ormore second control packets may be transmitted to a second wirelessdevice employing the third plurality of OFDM subcarriers of the thirdplurality of OFDM symbols of the subframe. The transmission of the oneor more second control packets to the second wireless device employingthe third plurality of OFDM subcarriers of the third plurality of OFDMsymbols of the subframe may use a third precoding matrix. The channelstate information reference signal may be transmitted on antenna portsused for transmission of the one or more data packets and the one ormore control packets. The first channel state information may becomputed employing the channel state information reference signals onantenna ports used for transmission of the one or more data packets. Thesecond channel state information may be computed employing the channelstate information reference signals on antenna ports used fortransmission of the one or more control packets.

The proposed transmission and reception mechanism introduced in theexample embodiments of this invention enable the transmitter to increasebandwidth efficiency in the system by efficiently employing control anddata radio resources. The proposed transmission and reception mechanismsprovide a method for transmission of reference signals and channelfeedback that increases system efficiency. A second carrier may be usedto provide additional capacity. In the example embodiments, the secondcarrier may not carry some of the physical channels, which are requiredfor example in LTE release 8, 9 and 10. This is one of the advantagescompared with existing technologies. The configuration information andsynchronization signals may be transmitted employing the first carrier,and this could improve system efficiency.

According to some of the various aspects of embodiments, the packets inthe downlink may be transmitted via downlink physical channels. Thecarrying packets in the uplink may be transmitted via uplink physicalchannels. The baseband data representing a downlink physical channel maybe defined in terms of at least one of the following actions: scramblingof coded bits in codewords to be transmitted on a physical channel;modulation of scrambled bits to generate complex-valued modulationsymbols; mapping of the complex-valued modulation symbols onto one orseveral transmission layers; precoding of the complex-valued modulationsymbols on layer(s) for transmission on the antenna port(s); mapping ofcomplex-valued modulation symbols for antenna port(s) to resourceelements; and/or generation of complex-valued time-domain OFDM signal(s)for antenna port(s).

Codeword, transmitted on the physical channel in one subframe, may bescrambled prior to modulation, resulting in a block of scrambled bits.The scrambling sequence generator may be initialized at the start ofsubframe(s). Codeword(s) may be modulated using QPSK, 16QAM, 64QAM,128QAM, and/or the like resulting in a block of complex-valuedmodulation symbols. The complex-valued modulation symbols for codewordsto be transmitted may be mapped onto one or several layers. Fortransmission on a single antenna port, a single layer may be used. Forspatial multiplexing, the number of layers may be less than or equal tothe number of antenna port(s) used for transmission of the physicalchannel. The case of a single codeword mapped to multiple layers may beapplicable when the number of cell-specific reference signals is four orwhen the number of UE-specific reference signals is two or larger. Fortransmit diversity, there may be one codeword and the number of layersmay be equal to the number of antenna port(s) used for transmission ofthe physical channel.

The precoder may receive a block of vectors from the layer mapping andgenerate a block of vectors to be mapped onto resources on the antennaport(s). Precoding for spatial multiplexing using antenna port(s) withcell-specific reference signals may be used in combination with layermapping for spatial multiplexing. Spatial multiplexing may support twoor four antenna ports and the set of antenna ports used may be {0,1} or{0, 1, 2, 3}. Precoding for transmit diversity may be used incombination with layer mapping for transmit diversity. The precodingoperation for transmit diversity may be defined for two and four antennaports. Precoding for spatial multiplexing using antenna ports withUE-specific reference signals may also, for example, be used incombination with layer mapping for spatial multiplexing. Spatialmultiplexing using antenna ports with UE-specific reference signals maysupport up to eight antenna ports. Reference signals may be pre-definedsignals that may be used by the receiver for decoding the receivedphysical signal, estimating the channel state, and/or other purposes.

For antenna port(s) used for transmission of the physical channel, theblock of complex-valued symbols may be mapped in sequence to resourceelements. In resource blocks in which UE-specific reference signals arenot transmitted the PDSCH may be transmitted on the same set of antennaports as the physical broadcast channel in the downlink (PBCH). Inresource blocks in which UE-specific reference signals are transmitted,the PDSCH may be transmitted, for example, on antenna port(s) {5, {7},{8}, or {7, 8, . . . , v+6}, where v is the number of layers used fortransmission of the PDSCH.

Common reference signal(s) may be transmitted in physical antennaport(s). Common reference signal(s) may be cell-specific referencesignal(s) (RS) used for demodulation and/or measurement purposes.Channel estimation accuracy using common reference signal(s) may bereasonable for demodulation (high RS density). Common referencesignal(s) may be defined for LTE technologies, LTE-advancedtechnologies, and/or the like. Demodulation reference signal(s) may betransmitted in virtual antenna port(s) (i.e., layer or stream). Channelestimation accuracy using demodulation reference signal(s) may bereasonable within allocated time/frequency resources. Demodulationreference signal(s) may be defined for LTE-advanced technology and maynot be applicable to LTE technology. Measurement reference signal(s),may also called CSI (channel state information) reference signal(s), maybe transmitted in physical antenna port(s) or virtualized antennaport(s). Measurement reference signal(s) may be Cell-specific RS usedfor measurement purposes. Channel estimation accuracy may be relativelylower than demodulation RS. CSI reference signal(s) may be defined forLTE-advanced technology and may not be applicable to LTE technology.

In at least one of the various embodiments, uplink physical channel(s)may correspond to a set of resource elements carrying informationoriginating from higher layers. The following example uplink physicalchannel(s) may be defined for uplink: a) Physical Uplink Shared Channel(PUSCH), b) Physical Uplink Control Channel (PUCCH), c) Physical RandomAccess Channel (PRACH), and/or the like. Uplink physical signal(s) maybe used by the physical layer and may not carry information originatingfrom higher layers. For example, reference signal(s) may be consideredas uplink physical signal(s). Transmitted signal(s) in slot(s) may bedescribed by one or several resource grids including, for example,subcarriers and SC-FDMA or OFDMA symbols. Antenna port(s) may be definedsuch that the channel over which symbol(s) on antenna port(s) may beconveyed and/or inferred from the channel over which other symbol(s) onthe same antenna port(s) is/are conveyed. There may be one resource gridper antenna port. The antenna port(s) used for transmission of physicalchannel(s) or signal(s) may depend on the number of antenna port(s)configured for the physical channel(s) or signal(s).

Element(s) in a resource grid may be called a resource element. Aphysical resource block may be defined as N consecutive SC-FDMA symbolsin the time domain and/or M consecutive subcarriers in the frequencydomain, wherein M and N may be pre-defined integer values. Physicalresource block(s) in uplink(s) may comprise of M.times.N resourceelements. For example, a physical resource block may correspond to oneslot in the time domain and 180 kHz in the frequency domain. Basebandsignal(s) representing the physical uplink shared channel may be definedin terms of: a) scrambling, b) modulation of scrambled bits to generatecomplex-valued symbols, c) mapping of complex-valued modulation symbolsonto one or several transmission layers, d) transform precoding togenerate complex-valued symbols, e) precoding of complex-valued symbols,f) mapping of precoded complex-valued symbols to resource elements, g)generation of complex-valued time-domain SC-FDMA signal(s) for antennaport(s), and/or the like.

For codeword(s), block(s) of bits may be scrambled with UE-specificscrambling sequence(s) prior to modulation, resulting in block(s) ofscrambled bits. Complex-valued modulation symbols for codeword(s) to betransmitted may be mapped onto one, two, or more layers. For spatialmultiplexing, layer mapping(s) may be performed according to pre-definedformula (s). The number of layers may be less than or equal to thenumber of antenna port(s) used for transmission of physical uplinkshared channel(s). The example of a single codeword mapped to multiplelayers may be applicable when the number of antenna port(s) used forPUSCH is, for example, four. For layer(s), the block of complex-valuedsymbols may be divided into multiple sets, each corresponding to oneSC-FDMA symbol. Transform precoding may be applied. For antenna port(s)used for transmission of the PUSCH in a subframe, block(s) ofcomplex-valued symbols may be multiplied with an amplitude scalingfactor in order to conform to a required transmit power, and mapped insequence to physical resource block(s) on antenna port(s) and assignedfor transmission of PUSCH.

According to some of the various embodiments, data may arrive to thecoding unit in the form of two transport blocks every transmission timeinterval (TTI) per UL cell. The following coding actions may beidentified for transport block(s) of an uplink carrier: a) Add CRC tothe transport block, b) Code block segmentation and code block CRCattachment, c) Channel coding of data and control information, d) Ratematching, e) Code block concatenation. f) Multiplexing of data andcontrol information, g) Channel interleaver, h) Error detection may beprovided on UL-SCH (uplink shared channel) transport block(s) through aCyclic Redundancy Check (CRC), and/or the like. Transport block(s) maybe used to calculate CRC parity bits. Code block(s) may be delivered tochannel coding block(s). Code block(s) may be individually turboencoded. Turbo coded block(s) may be delivered to rate matchingblock(s).

Physical uplink control channel(s) (PUCCH) may carry uplink controlinformation. Simultaneous transmission of PUCCH and PUSCH from the sameUE may be supported if enabled by higher layers. For a type 2 framestructure, the PUCCH may not be transmitted in the UpPTS field. PUCCHmay use one resource block in each of the two slots in a subframe.Resources allocated to UE and PUCCH configuration(s) may be transmittedvia control messages. PUCCH may comprise: a) positive and negativeacknowledgements for data packets transmitted at least one downlinkcarrier, b) channel state information for at least one downlink carrier,c) scheduling request, and/or the like.

According to some of the various aspects of embodiments, cell search maybe the procedure by which a wireless device may acquire time andfrequency synchronization with a cell and may detect the physical layerCell ID of that cell (transmitter). An example embodiment forsynchronization signal and cell search is presented below. A cell searchmay support a scalable overall transmission bandwidth corresponding to 6resource blocks and upwards. Primary and secondary synchronizationsignals may be transmitted in the downlink and may facilitate cellsearch. For example, 504 unique physical-layer cell identities may bedefined using synchronization signals. The physical-layer cellidentities may be grouped into 168 unique physical-layer cell-identitygroups, group(s) containing three unique identities. The grouping may besuch that physical-layer cell identit(ies) is part of a physical-layercell-identity group. A physical-layer cell identity may be defined by anumber in the range of 0 to 167, representing the physical-layercell-identity group, and a number in the range of 0 to 2, representingthe physical-layer identity within the physical-layer cell-identitygroup. The synchronization signal may include a primary synchronizationsignal and a secondary synchronization signal.

According to some of the various aspects of embodiments, the sequenceused for a primary synchronization signal may be generated from afrequency-domain Zadoff-Chu sequence according to a pre-defined formula.A Zadoff-Chu root sequence index may also be predefined in aspecification. The mapping of the sequence to resource elements maydepend on a frame structure. The wireless device may not assume that theprimary synchronization signal is transmitted on the same antenna portas any of the downlink reference signals. The wireless device may notassume that any transmission instance of the primary synchronizationsignal is transmitted on the same antenna port, or ports, used for anyother transmission instance of the primary synchronization signal. Thesequence may be mapped to the resource elements according to apredefined formula.

For FDD frame structure, a primary synchronization signal may be mappedto the last OFDM symbol in slots 0 and 10. For TDD frame structure, theprimary synchronization signal may be mapped to the third OFDM symbol insubframes 1 and 6. Some of the resource elements allocated to primary orsecondary synchronization signals may be reserved and not used fortransmission of the primary synchronization signal.

According to some of the various aspects of embodiments, the sequenceused for a secondary synchronization signal may be an interleavedconcatenation of two length-31 binary sequences. The concatenatedsequence may be scrambled with a scrambling sequence given by a primarysynchronization signal. The combination of two length-31 sequencesdefining the secondary synchronization signal may differ betweensubframe 0 and subframe 5 according to predefined formula (s). Themapping of the sequence to resource elements may depend on the framestructure. In a subframe for FDD frame structure and in a half-frame forTDD frame structure, the same antenna port as for the primarysynchronization signal may be used for the secondary synchronizationsignal. The sequence may be mapped to resource elements according to apredefined formula.

Example embodiments for the physical channels configuration will now bepresented. Other examples may also be possible. A physical broadcastchannel may be scrambled with a cell-specific sequence prior tomodulation, resulting in a block of scrambled bits. PBCH may bemodulated using QPSK, and/or the like. The block of complex-valuedsymbols for antenna port(s) may be transmitted during consecutive radioframes, for example, four consecutive radio frames. In some embodimentsthe PBCH data may arrive to the coding unit in the form of a onetransport block every transmission time interval (TTI) of 40 ms. Thefollowing coding actions may be identified. Add CRC to the transportblock, channel coding, and rate matching. Error detection may beprovided on PBCH transport blocks through a Cyclic Redundancy Check(CRC). The transport block may be used to calculate the CRC parity bits.The parity bits may be computed and attached to the BCH (broadcastchannel) transport block. After the attachment, the CRC bits may bescrambled according to the transmitter transmit antenna configuration.Information bits may be delivered to the channel coding block and theymay be tail biting convolutionally encoded. A tail bitingconvolutionally coded block may be delivered to the rate matching block.The coded block may be rate matched before transmission.

A master information block may be transmitted in PBCH and may includesystem information transmitted on broadcast channel(s). The masterinformation block may include downlink bandwidth, system framenumber(s), and PHICH (physical hybrid-ARQ indicator channel)configuration. Downlink bandwidth may be the transmission bandwidthconfiguration, in terms of resource blocks in a downlink, for example 6may correspond to 6 resource blocks, 15 may correspond to 15 resourceblocks and so on. System frame number(s) may define the N (for exampleN=8) most significant bits of the system frame number. The M (forexample M=2) least significant bits of the SFN may be acquiredimplicitly in the PBCH decoding. For example, timing of a 40 ms PBCH TTImay indicate 2 least significant bits (within 40 ms PBCH TTI, the firstradio frame: 00, the second radio frame: 01, the third radio frame: 10,the last radio frame: 11). One value may apply for other carriers in thesame sector of a base station (the associated functionality is common(e.g. not performed independently for each cell). PHICH configuration(s)may include PHICH duration, which may be normal (e.g. one symbolduration) or extended (e.g. 3 symbol duration).

Physical control format indicator channel(s) (PCFICH) may carryinformation about the number of OFDM symbols used for transmission ofPDCCHs (physical downlink control channel) in a subframe. The set ofOFDM symbols possible to use for PDCCH in a subframe may depend on manyparameters including, for example, downlink carrier bandwidth, in termsof downlink resource blocks. PCFICH transmitted in one subframe may bescrambled with cell-specific sequence(s) prior to modulation, resultingin a block of scrambled bits. A scrambling sequence generator(s) may beinitialized at the start of subframe(s). Block (s) of scrambled bits maybe modulated using QPSK. Block(s) of modulation symbols may be mapped toat least one layer and precoded resulting in a block of vectorsrepresenting the signal for at least one antenna port. Instances ofPCFICH control channel(s) may indicate one of several (e.g. 3) possiblevalues after being decoded. The range of possible values of instance(s)of the first control channel may depend on the first carrier bandwidth.

According to some of the various embodiments, physical downlink controlchannel(s) may carry scheduling assignments and other controlinformation. The number of resource-elements not assigned to PCFICH orPHICH may be assigned to PDCCH. PDCCH may support multiple formats.Multiple PDCCH packets may be transmitted in a subframe. PDCCH may becoded by tail biting convolutionally encoder before transmission. PDCCHbits may be scrambled with a cell-specific sequence prior to modulation,resulting in block(s) of scrambled bits. Scrambling sequencegenerator(s) may be initialized at the start of subframe(s). Block(s) ofscrambled bits may be modulated using QPSK. Block(s) of modulationsymbols may be mapped to at least one layer and precoded resulting in ablock of vectors representing the signal for at least one antenna port.PDCCH may be transmitted on the same set of antenna ports as the PBCH,wherein PBCH is a physical broadcast channel broadcasting at least onebasic system information field.

According to some of the various embodiments, scheduling controlpacket(s) may be transmitted for packet(s) or group(s) of packetstransmitted in downlink shared channel(s). Scheduling control packet(s)may include information about subcarriers used for packettransmission(s). PDCCH may also provide power control commands foruplink channels. OFDM subcarriers that are allocated for transmission ofPDCCH may occupy the bandwidth of downlink carrier(s). PDCCH channel(s)may carry a plurality of downlink control packets in subframe(s). PDCCHmay be transmitted on downlink carrier(s) starting from the first OFDMsymbol of subframe(s), and may occupy up to multiple symbol duration(s)(e.g. 3 or 4).

According to some of the various embodiments, PHICH may carry thehybrid-ARQ (automatic repeat request) ACK/NACK. Multiple PHICHs mappedto the same set of resource elements may constitute a PHICH group, wherePHICHs within the same PHICH group may be separated through differentorthogonal sequences. PHICH resource(s) may be identified by the indexpair (group, sequence), where group(s) may be the PHICH group number(s)and sequence(s) may be the orthogonal sequence index within thegroup(s). For frame structure type 1, the number of PHICH groups maydepend on parameters from higher layers (RRC). For frame structure type2, the number of PHICH groups may vary between downlink subframesaccording to a pre-defined arrangement. Block(s) of bits transmitted onone PHICH in one subframe may be modulated using BPSK or QPSK, resultingin a block(s) of complex-valued modulation symbols. Block(s) ofmodulation symbols may be symbol-wise multiplied with an orthogonalsequence and scrambled, resulting in a sequence of modulation symbols

Other arrangements for PCFICH, PHICH, PDCCH, and/or PDSCH may besupported. The configurations presented here are for example purposes.In another example, resources PCFICH, PHICH, and/or PDCCH radioresources may be transmitted in radio resources including a subset ofsubcarriers and pre-defined time duration in each or some of thesubframes. In an example, PUSCH resource(s) may start from the firstsymbol. In another example embodiment, radio resource configuration(s)for PUSCH, PUCCH, and/or PRACH (physical random access channel) may usea different configuration. For example, channels may be timemultiplexed, or time/frequency multiplexed when mapped to uplink radioresources.

According to some of the various aspects of embodiments, the physicallayer random access preamble may comprise a cyclic prefix of length Tcpand a sequence part of length Tseq. The parameter values may bepre-defined and depend on the frame structure and a random accessconfiguration. In an example embodiment, Tcp may be 0.1 msec, and Tseqmay be 0.9 msec. Higher layers may control the preamble format. Thetransmission of a random access preamble, if triggered by the MAC layer,may be restricted to certain time and frequency resources. The start ofa random access preamble may be aligned with the start of thecorresponding uplink subframe at a wireless device.

According to an example embodiment, random access preambles may begenerated from Zadoff-Chu sequences with a zero correlation zone,generated from one or several root Zadoff-Chu sequences. In anotherexample embodiment, the preambles may also be generated using otherrandom sequences such as Gold sequences. The network may configure theset of preamble sequences a wireless device may be allowed to use.According to some of the various aspects of embodiments, there may be amultitude of preambles (e.g. 64) available in cell(s). From the physicallayer perspective, the physical layer random access procedure mayinclude the transmission of random access preamble(s) and random accessresponse(s). Remaining message(s) may be scheduled for transmission by ahigher layer on the shared data channel and may not be considered partof the physical layer random access procedure. For example, a randomaccess channel may occupy 6 resource blocks in a subframe or set ofconsecutive subframes reserved for random access preamble transmissions.

According to some of the various embodiments, the following actions maybe followed for a physical random access procedure: 1) layer 1 proceduremay be triggered upon request of a preamble transmission by higherlayers; 2) a preamble index, a target preamble received power, acorresponding RA-RNTI (random access-radio network temporary identifier)and/or a PRACH resource may be indicated by higher layers as part of arequest; 3) a preamble transmission power P_PRACH may be determined; 4)a preamble sequence may be selected from the preamble sequence set usingthe preamble index; 5) a single preamble may be transmitted usingselected preamble sequence(s) with transmission power P_PRACH on theindicated PRACH resource; 6) detection of a PDCCH with the indicated RARmay be attempted during a window controlled by higher layers; and/or thelike. If detected, the corresponding downlink shared channel transportblock may be passed to higher layers. The higher layers may parsetransport block(s) and/or indicate an uplink grant to the physicallayer(s).

According to some of the various aspects of embodiments, a random accessprocedure may be initiated by a physical downlink control channel(PDCCH) order and/or by the MAC sublayer in a wireless device. If awireless device receives a PDCCH transmission consistent with a PDCCHorder masked with its radio identifier, the wireless device may initiatea random access procedure. Preamble transmission(s) on physical randomaccess channel(s) (PRACH) may be supported on a first uplink carrier andreception of a PDCCH order may be supported on a first downlink carrier.

Before a wireless device initiates transmission of a random accesspreamble, it may access one or many of the following types ofinformation: a) available set(s) of PRACH resources for the transmissionof a random access preamble; b) group(s) of random access preambles andset(s) of available random access preambles in group(s); c) randomaccess response window size(s); d) power-ramping factor(s); e) maximumnumber(s) of preamble transmission(s); f) initial preamble power; g)preamble format based offset(s); h) contention resolution timer(s);and/or the like. These parameters may be updated from upper layers ormay be received from the base station before random access procedure(s)may be initiated.

According to some of the various aspects of embodiments, a wirelessdevice may select a random access preamble using available information.The preamble may be signaled by a base station or the preamble may berandomly selected by the wireless device. The wireless device maydetermine the next available subframe containing PRACH permitted byrestrictions given by the base station and the physical layer timingrequirements for TDD or FDD. Subframe timing and the timing oftransmitting the random access preamble may be determined based, atleast in part, on synchronization signals received from the base stationand/or the information received from the base station. The wirelessdevice may proceed to the transmission of the random access preamblewhen it has determined the timing. The random access preamble may betransmitted on a second plurality of subcarriers on the first uplinkcarrier.

According to some of the various aspects of embodiments, once a randomaccess preamble is transmitted, a wireless device may monitor the PDCCHof a first downlink carrier for random access response(s), in a randomaccess response window. There may be a pre-known identifier in PDCCHthat indentifies a random access response. The wireless device may stopmonitoring for random access response(s) after successful reception of arandom access response containing random access preamble identifiersthat matches the transmitted random access preamble and/or a randomaccess response address to a wireless device identifier. A base stationrandom access response may include a time alignment command. Thewireless device may process the received time alignment command and mayadjust its uplink transmission timing according the time alignment valuein the command. For example, in a random access response, a timealignment command may be coded using 11 bits, where an amount of thetime alignment may be based on the value in the command. In an exampleembodiment, when an uplink transmission is required, the base stationmay provide the wireless device a grant for uplink transmission.

If no random access response is received within the random accessresponse window, and/or if none of the received random access responsescontains a random access preamble identifier corresponding to thetransmitted random access preamble, the random access response receptionmay be considered unsuccessful and the wireless device may, based on thebackoff parameter in the wireless device, select a random backoff timeand delay the subsequent random access transmission by the backoff time,and may retransmit another random access preamble.

According to some of the various aspects of embodiments, a wirelessdevice may transmit packets on an uplink carrier. Uplink packettransmission timing may be calculated in the wireless device using thetiming of synchronization signal(s) received in a downlink. Uponreception of a timing alignment command by the wireless device, thewireless device may adjust its uplink transmission timing. The timingalignment command may indicate the change of the uplink timing relativeto the current uplink timing. The uplink transmission timing for anuplink carrier may be determined using time alignment commands and/ordownlink reference signals.

According to some of the various aspects of embodiments, a timealignment command may indicate timing adjustment for transmission ofsignals on uplink carriers. For example, a time alignment command mayuse 6 bits. Adjustment of the uplink timing by a positive or a negativeamount indicates advancing or delaying the uplink transmission timing bya given amount respectively.

For a timing alignment command received on subframe n, the correspondingadjustment of the timing may be applied with some delay, for example, itmay be applied from the beginning of subframe n+6. When the wirelessdevice's uplink transmissions in subframe n and subframe n+1 areoverlapped due to the timing adjustment, the wireless device maytransmit complete subframe n and may not transmit the overlapped part ofsubframe n+1.

According to some of the various aspects of embodiments, a wirelessdevice may include a configurable timer (timeAlignmentTimer) that may beused to control how long the wireless device is considered uplink timealigned. When a timing alignment command MAC control element isreceived, the wireless device may apply the timing alignment command andstart or restart timeAlignmentTimer. The wireless device may not performany uplink transmission except the random access preamble transmissionwhen timeAlignmentTimer is not running or when it exceeds its limit. Thetime alignment command may substantially align frame and subframereception timing of a first uplink carrier and at least one additionaluplink carrier. According to some of the various aspects of embodiments,the time alignment command value range employed during a random accessprocess may be substantially larger than the time alignment commandvalue range during active data transmission. In an example embodiment,uplink transmission timing may be maintained on a per time alignmentgroup (TAG) basis. Carrier(s) may be grouped in TAGs, and TAG(s) mayhave their own downlink timing reference, time alignment timer, and/ortime alignment commands. Group(s) may have their own random accessprocess. Time alignment commands may be directed to a time alignmentgroup. The TAG, including the primary cell may be called a primary TAG(pTAG) and the TAG not including the primary cell may be called asecondary TAG (sTAG).

According to some of the various aspects of embodiments, controlmessage(s) or control packet(s) may be scheduled for transmission in aphysical downlink shared channel (PDSCH) and/or physical uplink sharedchannel PUSCH. PDSCH and PUSCH may carry control and datamessage(s)/packet(s). Control message(s) and/or packet(s) may beprocessed before transmission. For example, the control message(s)and/or packet(s) may be fragmented or multiplexed before transmission. Acontrol message in an upper layer may be processed as a data packet inthe MAC or physical layer. For example, system information block(s) aswell as data traffic may be scheduled for transmission in PDSCH. Datapacket(s) may be encrypted packets.

According to some of the various aspects of embodiments, data packet(s)may be encrypted before transmission to secure packet(s) from unwantedreceiver(s). Desired recipient(s) may be able to decrypt the packet(s).A first plurality of data packet(s) and/or a second plurality of datapacket(s) may be encrypted using an encryption key and at least oneparameter that may change substantially rapidly over time. Theencryption mechanism may provide a transmission that may not be easilyeavesdropped by unwanted receivers. The encryption mechanism may includeadditional parameter(s) in an encryption module that changessubstantially rapidly in time to enhance the security mechanism. Examplevarying parameter(s) may comprise various types of system counter(s),such as system frame number. Substantially rapidly may for example implychanging on a per subframe, frame, or group of subframes basis.Encryption may be provided by a PDCP layer between the transmitter andreceiver, and/or may be provided by the application layer. Additionaloverhead added to packet(s) by lower layers such as RLC, MAC, and/orPhysical layer may not be encrypted before transmission. In thereceiver, the plurality of encrypted data packet(s) may be decryptedusing a first decryption key and at least one first parameter. Theplurality of data packet(s) may be decrypted using an additionalparameter that changes substantially rapidly over time.

According to some of the various aspects of embodiments, a wirelessdevice may be preconfigured with one or more carriers. When the wirelessdevice is configured with more than one carrier, the base station and/orwireless device may activate and/or deactivate the configured carriers.One of the carriers (the primary carrier) may always be activated. Othercarriers may be deactivated by default and/or may be activated by a basestation when needed. A base station may activate and deactivate carriersby sending an activation/deactivation MAC control element. Furthermore,the UE may maintain a carrier deactivation timer per configured carrierand deactivate the associated carrier upon its expiry. The same initialtimer value may apply to instance(s) of the carrier deactivation timer.The initial value of the timer may be configured by a network. Theconfigured carriers (unless the primary carrier) may be initiallydeactivated upon addition and after a handover.

According to some of the various aspects of embodiments, if a wirelessdevice receives an activation/deactivation MAC control elementactivating the carrier, the wireless device may activate the carrier,and/or may apply normal carrier operation including: sounding referencesignal transmissions on the carrier, CQI (channel qualityindicator)/PMI(precoding matrix indicator)/RI(ranking indicator)reporting for the carrier, PDCCH monitoring on the carrier, PDCCHmonitoring for the carrier, start or restart the carrier deactivationtimer associated with the carrier, and/or the like. If the devicereceives an activation/deactivation MAC control element deactivating thecarrier, and/or if the carrier deactivation timer associated with theactivated carrier expires, the base station or device may deactivate thecarrier, and may stop the carrier deactivation timer associated with thecarrier, and/or may flush HARQ buffers associated with the carrier.

If PDCCH on a carrier scheduling the activated carrier indicates anuplink grant or a downlink assignment for the activated carrier, thedevice may restart the carrier deactivation timer associated with thecarrier. When a carrier is deactivated, the wireless device may nottransmit SRS (sounding reference signal) for the carrier, may not reportCQI/PMI/RI for the carrier, may not transmit on UL-SCH for the carrier,may not monitor the PDCCH on the carrier, and/or may not monitor thePDCCH for the carrier.

A process to assign subcarriers to data packets may be executed by a MAClayer scheduler. The decision on assigning subcarriers to a packet maybe made based on data packet size, resources required for transmissionof data packets (number of radio resource blocks), modulation and codingassigned to data packet(s), QoS required by the data packets (i.e. QoSparameters assigned to data packet bearer), the service class of asubscriber receiving the data packet, or subscriber device capability, acombination of the above, and/or the like.

According to some of the various aspects of embodiments, packets may bereferred to service data units and/or protocols data units at Layer 1,Layer 2 and/or Layer 3 of the communications network. Layer 2 in an LTEnetwork may include three sub-layers: PDCP sub-layer, RLC sub-layer, andMAC sub-layer. A layer 2 packet may be a PDCP packet, an RLC packet or aMAC layer packet. Layer 3 in an LTE network may be Internet Protocol(IP) layer, and a layer 3 packet may be an IP data packet. Packets maybe transmitted and received via an air interface physical layer. Apacket at the physical layer may be called a transport block. Many ofthe various embodiments may be implemented at one or many differentcommunication network layers. For example, some of the actions may beexecuted by the PDCP layer and some others by the MAC layer.

According to some of the various aspects of embodiments, subcarriersand/or resource blocks may comprise a plurality of physical subcarriersand/or resource blocks. In another example embodiment, subcarriers maybe a plurality of virtual and/or logical subcarriers and/or resourceblocks.

According to some of the various aspects of embodiments, a radio bearermay be a GBR (guaranteed bit rate) bearer and/or a non-GBR bearer. A GBRand/or guaranteed bit rate bearer may be employed for transfer ofreal-time packets, and/or a non-GBR bearer may be used for transfer ofnon-real-time packets. The non-GBR bearer may be assigned a plurality ofattributes including: a scheduling priority, an allocation and retentionpriority, a portable device aggregate maximum bit rate, and/or the like.These parameters may be used by the scheduler in scheduling non-GBRpackets. GBR bearers may be assigned attributes such as delay, jitter,packet loss parameters, and/or the like.

According to some of the various aspects of embodiments, subcarriers mayinclude data subcarrier symbols and pilot subcarrier symbols. Pilotsymbols may not carry user data, and may be included in the transmissionto help the receiver to perform synchronization, channel estimationand/or signal quality detection. Base stations and wireless devices(wireless receiver) may use different methods to generate and transmitpilot symbols along with information symbols.

According to some of the various aspects of embodiments, the transmitterin the disclosed embodiments of the present invention may be a wirelessdevice (also called user equipment), a base station (also calledeNodeB), a relay node transmitter, and/or the like. The receiver in thedisclosed embodiments of the present invention may be a wireless device(also called user equipment-UE), a base station (also called eNodeB), arelay node receiver, and/or the like. According to some of the variousaspects of embodiments of the present invention, layer 1 (physicallayer) may be based on OFDMA or SC-FDMA. Time may be divided intoframe(s) with fixed duration. Frame(s) may be divided into substantiallyequally sized subframes, and subframe(s) may be divided intosubstantially equally sized slot(s). A plurality of OFDM or SC-FDMAsymbol(s) may be transmitted in slot(s). OFDMA or SC-FDMA symbol(s) maybe grouped into resource block(s). A scheduler may assign resource(s) inresource block unit(s), and/or a group of resource block unit(s).Physical resource block(s) may be resources in the physical layer, andlogical resource block(s) may be resource block(s) used by the MAClayer. Similar to virtual and physical subcarriers, resource block(s)may be mapped from logical to physical resource block(s). Logicalresource block(s) may be contiguous, but corresponding physical resourceblock(s) may be non-contiguous. Some of the various embodiments of thepresent invention may be implemented at the physical or logical resourceblock level(s).

According to some of the various aspects of embodiments, layer 2transmission may include PDCP (packet data convergence protocol), RLC(radio link control), MAC (media access control) sub-layers, and/or thelike. MAC may be responsible for the multiplexing and mapping of logicalchannels to transport channels and vice versa. A MAC layer may performchannel mapping, scheduling, random access channel procedures, uplinktiming maintenance, and/or the like.

According to some of the various aspects of embodiments, the MAC layermay map logical channel(s) carrying RLC PDUs (packet data unit) totransport channel(s). For transmission, multiple SDUs (service dataunit) from logical channel(s) may be mapped to the Transport Block (TB)to be sent over transport channel(s). For reception, TBs from transportchannel(s) may be demultiplexed and assigned to corresponding logicalchannel(s). The MAC layer may perform scheduling related function(s) inboth the uplink and downlink and thus may be responsible for transportformat selection associated with transport channel(s). This may includeHARQ functionality. Since scheduling may be done at the base station,the MAC layer may be responsible for reporting scheduling relatedinformation such as UE (user equipment or wireless device) bufferoccupancy and power headroom. It may also handle prioritization fromboth an inter-UE and intra-UE logical channel perspective. MAC may alsobe responsible for random access procedure(s) for the uplink that may beperformed following either a contention and non-contention basedprocess. UE may need to maintain timing synchronization with cell(s).The MAC layer may perform procedure(s) for periodic synchronization.

According to some of the various aspects of embodiments, the MAC layermay be responsible for the mapping of multiple logical channel(s) totransport channel(s) during transmission(s), and demultiplexing andmapping of transport channel data to logical channel(s) duringreception. A MAC PDU may include of a header that describes the formatof the PDU itself, which may include control element(s), SDUs, Padding,and/or the like. The header may be composed of multiple sub-headers, onefor constituent part(s) of the MAC PDU. The MAC may also operate in atransparent mode, where no header may be pre-pended to the PDU.Activation command(s) may be inserted into packet(s) using a MAC controlelement.

According to some of the various aspects of embodiments, the MAC layerin some wireless device(s) may report buffer size(s) of either a singleLogical Channel Group (LCG) or a group of LCGs to a base station. An LCGmay be a group of logical channels identified by an LCG ID. The mappingof logical channel(s) to LCG may be set up during radio configuration.Buffer status report(s) may be used by a MAC scheduler to assign radioresources for packet transmission from wireless device(s). HARQ and ARQprocesses may be used for packet retransmission to enhance thereliability of radio transmission and reduce the overall probability ofpacket loss.

According to some of the various aspects of embodiments, an RLCsub-layer may control the applicability and functionality of errorcorrection, concatenation, segmentation, re-segmentation, duplicatedetection, in-sequence delivery, and/or the like. Other functions of RLCmay include protocol error detection and recovery, and/or SDU discard.The RLC sub-layer may receive data from upper layer radio bearer(s)(signaling and data) called service data unit(s) (SDU). The transmissionentities in the RLC layer may convert RLC SDUs to RLC PDU afterperforming functions such as segmentation, concatenation, adding RLCheader(s), and/or the like. In the other direction, receiving entitiesmay receive RLC PDUs from the MAC layer. After performing reordering,the PDUs may be assembled back into RLC SDUs and delivered to the upperlayer. RLC interaction with a MAC layer may include: a) data transferfor uplink and downlink through logical channel(s); b) MAC notifies RLCwhen a transmission opportunity becomes available, including the size oftotal number of RLC PDUs that may be transmitted in the currenttransmission opportunity, and/or c) the MAC entity at the transmittermay inform RLC at the transmitter of HARQ transmission failure.

According to some of the various aspects of embodiments, PDCP (packetdata convergence protocol) may comprise a layer 2 sub-layer on top ofRLC sub-layer. The PDCP may be responsible for a multitude of functions.First, the PDCP layer may transfer user plane and control plane data toand from upper layer(s). PDCP layer may receive SDUs from upper layer(s)and may send PDUs to the lower layer(s). In other direction, PDCP layermay receive PDUs from the lower layer(s) and may send SDUs to upperlayer(s). Second, the PDCP may be responsible for security functions. Itmay apply ciphering (encryption) for user and control plane bearers, ifconfigured. It may also perform integrity protection for control planebearer(s), if configured. Third, the PDCP may perform header compressionservice(s) to improve the efficiency of over the air transmission. Theheader compression may be based on robust header compression (ROHC).ROHC may be performed on VOIP packets. Fourth, the PDCP may beresponsible for in-order delivery of packet(s) and duplicate detectionservice(s) to upper layer(s) after handover(s). After handover, thesource base station may transfer unacknowledged packet(s)s to targetbase station when operating in RLC acknowledged mode (AM). The targetbase station may forward packet(s)s received from the source basestation to the UE (user equipment).

In this specification, “a” and “an” and similar phrases are to beinterpreted as “at least one” and “one or more.” In this specification,the term “may” is to be interpreted as “may, for example,” In otherwords, the term “may” is indicative that the phrase following the term“may” is an example of one of a multitude of suitable possibilities thatmay, or may not, be employed to one or more of the various embodiments.If A and B are sets and every element of A is also an element of B, A iscalled a subset of B. In this specification, only non-empty sets andsubsets are considered. For example, possible subsets of B={cell1,cell2} are: {cell1}, {cell2}, and {cell1, cell2}.

Many of the elements described in the disclosed embodiments may beimplemented as modules. A module is defined here as an isolatableelement that performs a defined function and has a defined interface toother elements. The modules described in this disclosure may beimplemented in hardware, software in combination with hardware,firmware, wetware (i.e hardware with a biological element) or acombination thereof, all of which are behaviorally equivalent. Forexample, modules may be implemented as a software routine written in acomputer language configured to be executed by a hardware machine (suchas C, C++, Fortran, Java, Basic, Matlab or the like) or amodeling/simulation program such as Simulink, Stateflow, GNU Octave, orLab VIEWMathScript. Additionally, it may be possible to implementmodules using physical hardware that incorporates discrete orprogrammable analog, digital and/or quantum hardware. Examples ofprogrammable hardware comprise: computers, microcontrollers,microprocessors, application-specific integrated circuits (ASICs); fieldprogrammable gate arrays (FPGAs); and complex programmable logic devices(CPLDs). Computers, microcontrollers and microprocessors are programmedusing languages such as assembly, C, C++ or the like. FPGAs, ASICs andCPLDs are often programmed using hardware description languages (HDL)such as VHSIC hardware description language (VHDL) or Verilog thatconfigure connections between internal hardware modules with lesserfunctionality on a programmable device. Finally, it needs to beemphasized that the above mentioned technologies are often used incombination to achieve the result of a functional module.

The disclosure of this patent document incorporates material which issubject to copyright protection. The copyright owner has no objection tothe facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the Patent and Trademark Officepatent file or records, for the limited purposes required by law, butotherwise reserves all copyright rights whatsoever.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example, and notlimitation. It will be apparent to persons skilled in the relevantart(s) that various changes in form and detail can be made thereinwithout departing from the spirit and scope. In fact, after reading theabove description, it will be apparent to one skilled in the relevantart(s) how to implement alternative embodiments. Thus, the presentembodiments should not be limited by any of the above describedexemplary embodiments. In particular, it should be noted that, forexample purposes, the above explanation has focused on the example(s)using FDD communication systems. However, one skilled in the art willrecognize that embodiments of the invention may also be implemented inTDD communication systems. The disclosed methods and systems may beimplemented in wireless or wireline systems. The features of variousembodiments presented in this invention may be combined. One or manyfeatures (method or system) of one embodiment may be implemented inother embodiments. Only a limited number of example combinations areshown to indicate to one skilled in the art the possibility of featuresthat may be combined in various embodiments to create enhancedtransmission and reception systems and methods.

In addition, it should be understood that any figures which highlightthe functionality and advantages, are presented for example purposesonly. The disclosed architecture is sufficiently flexible andconfigurable, such that it may be utilized in ways other than thatshown. For example, the actions listed in any flowchart may bere-ordered or only optionally used in some embodiments.

Further, the purpose of the Abstract of the Disclosure is to enable theU.S. Patent and Trademark Office and the public generally, andespecially the scientists, engineers and practitioners in the art whoare not familiar with patent or legal terms or phraseology, to determinequickly from a cursory inspection the nature and essence of thetechnical disclosure of the application. The Abstract of the Disclosureis not intended to be limiting as to the scope in any way.

Finally, it is the applicant's intent that only claims that include theexpress language “means for” or “step for” be interpreted under 35U.S.C. 112, paragraph 6. Claims that do not expressly include the phrase“means for” or “step for” are not to be interpreted under 35 U.S.C. 112,paragraph 6.

1. A system comprising: a base station and a wireless device, whereinthe base station comprises: one or more processors; and memory storinginstructions that, when executed by the one or more processors, causethe base station to: receive, from the wireless device, channel stateinformation (CSI) comprising a precoding matrix indicator; determine,based on the precoding matrix indicator: a first precoding matrix fortransmission of a downlink data channel to the wireless device; and asecond precoding matrix for transmission of a downlink control channelto the wireless device, wherein the second precoding matrix is differentfrom the first precoding matrix, and wherein the downlink controlchannel is associated with the downlink data channel; transmit, in asubframe: the downlink data channel using the first precoding matrix;and at least one first reference signal associated with the downlinkdata channel; and transmit, in the subframe: the downlink controlchannel using the second precoding matrix; and at least one secondreference signal associated with the downlink control channel, andwherein the wireless device comprises: one or more processors; andmemory storing instructions that, when executed by the one or moreprocessors of the wireless device, cause the wireless device to transmitthe CSI and receive the downlink data channel and the downlink controlchannel.
 2. The system of claim 1, wherein the instructions in thememory of the base station, when executed by the one or more processorsof the base station, cause the base station to: transmit the downlinkdata channel via a first plurality of orthogonal frequency divisionmultiplexed (OFDM) subcarriers, and transmit the downlink controlchannel via a second plurality of OFDM subcarriers that is differentfrom the first plurality of OFDM subcarriers.
 3. The system of claim 1,wherein the instructions in the memory of the base station, whenexecuted by the one or more processors of the base station, cause thebase station to transmit the at least one second reference signalassociated with the downlink control channel by using a smaller numberof antenna ports than the transmitting the at least one first referencesignal associated with the downlink data channel.
 4. The system of claim1, wherein the second precoding matrix uses a smaller number ofmultiple-input-multiple-output (MIMO) layers than the first precodingmatrix.
 5. The system of claim 1, wherein the second precoding matrix isa column vector.
 6. The system of claim 1, wherein the at least onesecond reference signal associated with the downlink control channelcomprises at least two orthogonal reference signals.
 7. The system ofclaim 1, wherein the instructions in the memory of the base station,when executed by the one or more processors of the base station, causethe base station to transmit, via the downlink control channel and usingmultiple user multiple-input-multiple-output (MIMO), one or more controlpackets.
 8. The system of claim 1, wherein the second precoding matrixis a submatrix of the first precoding matrix.
 9. The system of claim 1,wherein the second precoding matrix is based, at least in part, on alinear transformation on a subset of rows and columns of the firstprecoding matrix.
 10. The system of claim 1, wherein the secondprecoding matrix has a smaller number of columns than the firstprecoding matrix.
 11. The system of claim 1, wherein the at least onefirst reference signal comprises a demodulation reference signal. 12.The system of claim 1, wherein the at least one second reference signalcomprises a demodulation reference signal.
 13. A method comprising:transmitting, by a wireless device and to a base station, channel stateinformation (CSI) comprising a precoding matrix indicator; receiving, ina subframe: a downlink data channel that is precoded using a firstprecoding matrix that is based on the precoding matrix indicator; and atleast one first reference signal associated with the downlink datachannel; and receiving, in the subframe: a downlink control channel thatis associated with the downlink data channel and that is precoded usinga second precoding matrix that is based on the precoding matrixindicator; and at least one second reference signal associated with thedownlink control channel.
 14. The method of claim 13, wherein: thedownlink data channel is received via a first plurality of orthogonalfrequency division multiplexed (OFDM) subcarriers, and the downlinkcontrol channel is received via a second plurality of OFDM subcarriersthat is different from the first plurality of OFDM subcarriers.
 15. Themethod of claim 13, wherein the second precoding matrix uses a smallernumber of multiple-input-multiple-output (MIMO) layers than the firstprecoding matrix.
 16. The method of claim 13, wherein the secondprecoding matrix is a column vector.
 17. The method of claim 13, whereinthe at least one second reference signal associated with the downlinkcontrol channel comprises at least two orthogonal reference signals. 18.The method of claim 13, wherein the second precoding matrix is asubmatrix of the first precoding matrix.
 19. The method of claim 13,wherein the second precoding matrix is based, at least in part, on alinear transformation on a subset of rows and columns of the firstprecoding matrix.
 20. The method of claim 13, wherein the secondprecoding matrix has a smaller number of columns than the firstprecoding matrix.
 21. The method of claim 13, wherein the at least onefirst reference signal comprises a demodulation reference signal. 22.The method of claim 13, wherein the at least one second reference signalcomprises a demodulation reference signal.
 23. A wireless devicecomprising: one or more processors; and memory storing instructionsthat, when executed by the one or more processors, cause the wirelessdevice to: transmit, to a base station, channel state information (CSI)comprising a precoding matrix indicator; receive, in a subframe: adownlink data channel that is precoded using a first precoding matrixthat is based on the precoding matrix indicator; and at least one firstreference signal associated with the downlink data channel; and receive,in the subframe: a downlink control channel that is associated with thedownlink data channel and that is precoded using a second precodingmatrix that is based on the precoding matrix indicator; and at least onesecond reference signal associated with the downlink control channel.24. The wireless device of claim 23, wherein: the downlink data channelis received via a first plurality of orthogonal frequency divisionmultiplexed (OFDM) subcarriers, and the downlink control channel isreceived via a second plurality of OFDM subcarriers that is differentfrom the first plurality of OFDM subcarriers.
 25. The wireless device ofclaim 23, wherein the second precoding matrix uses a smaller number ofmultiple-input-multiple-output (MIMO) layers than the first precodingmatrix.
 26. The wireless device of claim 23, wherein the secondprecoding matrix is a column vector.
 27. The wireless device of claim23, wherein the at least one second reference signal associated with thedownlink control channel comprises at least two orthogonal referencesignals.
 28. The wireless device of claim 23, wherein the secondprecoding matrix is a submatrix of the first precoding matrix.
 29. Thewireless device of claim 23, wherein the second precoding matrix isbased, at least in part, on a linear transformation on a subset of rowsand columns of the first precoding matrix.
 30. The wireless device ofclaim 23, wherein the second precoding matrix has a smaller number ofcolumns than the first precoding matrix.
 31. The wireless device ofclaim 23, wherein the at least one first reference signal comprises ademodulation reference signal.
 32. The wireless device of claim 23,wherein the at least one second reference signal comprises ademodulation reference signal.